NEW YORK – Two dangerous flashpoints, in Europe and Asia, could bring the United States, Russia, and China into open conflict. The crises over Ukraine and Taiwan can be resolved, but all parties must respect the others’ legitimate security interests. Acknowledging those interests objectively will provide the basis for a lasting de-escalation of tensions.

Consider Ukraine. Although it undoubtedly has the right to sovereignty and safety from a Russian invasion, it does not have the right to undermine Russia’s security in the process.

The current Ukraine crisis is the result of overreach by both Russia and the US. Russia’s overreach lies in its 2014 annexation of Crimea and occupation of Ukraine’s industrial heartland in Donetsk and Luhansk; and in its ongoing efforts to keep Ukraine dependent on it for energy, industrial inputs, and markets. Ukraine has a legitimate interest in integrating more closely with the European Union economy, and it has signed an association agreement with the EU for that purpose. The Kremlin, however, fears that EU membership could be a stepping stone for Ukraine to join NATO.

The US, too, has been overreaching. In 2008, US President George W. Bush’s administration called for Ukraine to be invited to join NATO, an addition that would establish the Alliance’s presence on Russia’s long border with that country. This provocative proposal divided US allies, but NATO nonetheless confirmed that Ukraine could eventually be welcomed as a member, noting that Russia has no veto over who joins. When Russia violently annexed Crimea in 2014, one of its objectives was to ensure that NATO could never gain access to Russia’s Black Sea naval base and fleet.

Judging by the public transcripts of discussions between US President Joe Biden and Russian President Vladimir Putin this month, NATO enlargement to Ukraine remains on the table. Although France and Germany might well maintain their longstanding threat to veto any such bid for membership, Ukrainian and NATO officials have both reiterated that the choice to join lies with Ukraine. Moreover, a high-ranking Estonian parliamentarian has warned that walking back Ukraine’s right to join NATO would be tantamount to Britain’s appeasement of Hitler in 1938.

Yet American leaders who argue that Ukraine has the right to choose its own military alliance should reflect on their country’s own long history of categorical opposition to outside meddling in the Western hemisphere. This position was first expressed in the 1823 Monroe Doctrine, and it was on full display in the violent US reaction to Fidel Castro’s turn toward the Soviet Union after the 1959 Cuban Revolution.

Back then, US President Dwight D. Eisenhower declared that “Cuba has been handed over to the Soviet Union as an instrument with which to undermine our position in Latin America and the world.” He ordered the CIA to devise plans for an invasion. The result was the Bay of Pigs fiasco (under President John F. Kennedy), which lit the fuse for the 1962 Cuban Missile Crisis.

Countries cannot simply choose their military alliances, because such choices often have security implications for their neighbors. Following World War II, Austria and Finland both secured their independence and future prosperity by not joining NATO, as that would have provoked Soviet ire. Ukraine today should show the same prudence.

The issues in Taiwan are similar. Taiwan has the right to peace and democracy in accord with the concept of the “One China” policy, which has been the bedrock of China’s relations with the US since the days of Richard Nixon and Mao Zedong. The US is right to warn China against any unilateral military action toward Taiwan, as that would threaten global security and the world economy. Yet, just as Ukraine does not have the right to join NATO, Taiwan does not have the right to secede from China.

In recent years, however, some Taiwanese politicians have flirted with declaring independence, and some US politicians have taken liberties with the “One China” principle. Then President-elect Donald Trump started the US’ backsliding in December 2016, when he said, “I fully understand the ‘One China’ policy, but I don’t know why we have to be bound by a ‘One China’ policy unless we make a deal with China having to do with other things, including trade.”

Then, President Joe Biden provocatively included Taiwan in his Summit for Democracy this month, following US Secretary of State Antony Blinken’s recent advocacy for Taiwan’s “robust participation” in the United Nations system. Such US actions have greatly aggravated tensions with China.

Again, those US security analysts who argue that Taiwan is within its rights to declare independence should reflect on America’s own history. The US fought a civil war over the legitimacy of secession, and the secessionists lost. The US government would not tolerate Chinese support for a secessionist movement in, say, California (nor would European countries such as Spain, which has faced the real thing in Basque Country and Catalonia).

The risks of military escalation over Taiwan are compounded by NATO Secretary-General Jens Stoltenberg’s recent announcement that the alliance’s future rationale will include countering China. An alliance created to defend Western Europe from invasion by a now-defunct European power should not be repurposed as a US-led military alliance against an Asian power.

The Ukraine and Taiwan crises can be resolved peacefully and straightforwardly. NATO should take Ukraine’s membership off the table, and Russia should forswear any invasion. Ukraine should be free to orient its trade policies however it sees fit, provided that it abides by World Trade Organization principles.

Similarly, the US should make clear once again that it steadfastly opposes Taiwan’s secession and does not aim to “contain” China, especially by reorienting NATO. For its part, China should renounce unilateral military action against Taiwan and reaffirm the two-system principle, which many Taiwanese believe to be under imminent threat following the crackdown in Hong Kong.

No global structure of peace can be stable and secure unless all parties recognize others’ legitimate security interests. The best way for the major powers to begin to achieve that is to choose the path of mutual understanding and de-escalation over Ukraine and Taiwan.

STOCKHOLM – As reports pile up about Russia’s military mobilization on Ukraine’s border and the Kremlin’s diplomatic demands, questions abound. What is going on? What will come next? Will Russia invade?

In fact, Russian President Vladimir Putin is following an eight-year-old script.

In the fall of 2013, Putin’s government launched a multifaceted offensive to prevent Ukraine, Moldova, and Armenia from signing free-trade agreements with the European Union. That set off a gradually deepening crisis that would profoundly alter Ukraine’s domestic politics, Russia’s position in Europe, and the future of NATO. Less than a year later, Russia annexed Crimea and embarked on a barely disguised effort to dismantle the rest of Ukraine. The Kremlin then launched two more incursions into eastern Ukraine to save the separatist statelets that it had managed to set up there.

Since then, 14,000 people have died in this low-level “frozen” conflict. The EU and the United States regularly renew their sanctions on Russia, and the United Nations General Assembly regularly condemns Russia’s behavior and reaffirms the sanctity of state borders. Not only did Putin fail to derail the EU-Ukraine free-trade agreement; he also managed to transform Ukraine from a friendly neighbor into a country that regards Russia as dangerous and hostile. Invading other countries is a historically proven way to make lasting enemies.

Putin now faces the embarrassing prospect of being remembered as the Russian leader who lost Ukraine. He will have set his country back three centuries, to the time before Peter the Great. Even the collapse of the Soviet Union eventually may come to seem less important than Putin’s blunders over the past decade.

Nonetheless, Putin appears to have spent his COVID-19 isolation reading history. This summer, he produced a remarkable essay effectively calling for a greater Slavic empire. Suggesting that power over Ukraine and Belarus ultimately lies within the Kremlin’s walls, he made clear that he intends to recover what his previous miscalculations lost.

The subsequent evolution of Putin’s thinking is unknown. But it is plausible that he spotted weakness in the chaotic US exit from Afghanistan, and surmised that America is not keen on yet another foreign entanglement. Whatever Putin’s reasoning, he has since abandoned further dialogue with Ukraine’s leaders, sent German and French mediators packing, and concentrated a massive number of tanks in the border region. His goal is to pressure the US to agree to a series of radical demands for restructuring European security; chief among these is that the US rescind its promise, first made in 2008, that Ukraine will someday be invited to join NATO.

Putin’s strategic intent in 2014 – to stop the agreement with the EU – ultimately failed. Now, his immediate focus is on regional security issues. Russian officials and state media have been issuing shrill warnings and spinning ominous tales about the US placing missiles in Ukraine to strike Moscow. There is talk of genocide against Ukraine’s Russian-speaking population, and of Ukraine’s imminent entry into NATO.

None of these claims bears the faintest resemblance to the truth. But opinion polls suggest that the propaganda has been effective. Around 39% of Russians believe that war is imminent, and this figure is likely to grow as the Kremlin continues to stoke fear among the population.

In the meantime, Putin has tasked his diplomats with securing US and EU agreement to his maximalist formal demands for a new security order. The maneuver is eerily reminiscent of the infamous deal-making done at Yalta in 1945, when the Allied powers discussed how Germany and Europe would be carved up after World War II.

Yet while a further expansion of NATO is not in the cards, the Alliance will not accept an arrangement that denies any country the right to shape its own destiny. This issue is bigger than Ukraine. The president of Finland, which shares a long border with Russia, has been vocal in pointing out that the option of applying for NATO membership is key to his country’s security. Though he has no intention of launching a membership bid, nor can he allow any outside power to limit his country’s sovereignty. Likewise, countries across Central and Eastern Europe fear that giving in to one Kremlin demand will only invite more.

Is a diplomatic resolution still possible? The path is narrow, and time might be running out. There are proposals to place limits on, and improve the transparency of, conventional forces in Europe. But Russia has rejected many such proposals in the past, and complex arms negotiations would take considerable time. Moreover, these diplomatic options would not satisfy Putin’s wish to create a Greater Russia, suggesting that the Kremlin will not rule out military options.

These come in many shapes and sizes. A full-scale Russian invasion would undoubtedly lead to an open-ended conflict that, whatever the original intention, is bound to spill over Ukraine’s borders. If that happened, all options would be on the table for NATO. Severe sanctions and other measures would further squeeze Russia’s already dim economic prospects – even if it secures support from China. More to the point, NATO would finally roar forward to Russia’s border by deepening its presence in its member states that border Russia.

Given this foreseeable outcome, an invasion would be folly in the extreme. But this scenario cannot be ruled out. The Kremlin record of profound mistakes in its policy toward Ukraine is long. And while many in Moscow already doubt the rationality of Putin’s aggressive revisionism, their voices carry no weight.

Another more imminent possibility is that the Kremlin will try to provoke Ukraine into doing something that would justify a smaller-scale invasion of the kind we saw in 2014 and 2015. But the escalation risk would be severe, and even a small invasion would expose Russia to severely damaging consequences. Either way, the Kremlin has embarked on a dangerous path.

It is not too late to prevent Putin’s script from becoming a tragedy. Let us hope that he has not been reading Chekhov, who famously advised against introducing a gun in the first act unless it will be used in the second.

WASHINGTON, DC – Today’s Russia poses a clear and present danger to world peace. In July, President Vladimir Putin published a long article, “About the Historical Unity of Russians and Ukrainians,” effectively denying the legitimacy of Ukraine’s existence as an independent nation-state. He also has pursued a policy of military mobilization around Ukraine’s border, first in April and even more intensively in recent weeks. Senior Ukrainian and US officials, including President Joe Biden, are warning that Russia may launch a major ground war against Ukraine in early 2022.

Various causes of Russia’s aggressiveness have been suggested, but the most important one focuses on Russian decline, and whether this has made the country more dangerous. Is Putin genuinely intent on attacking Ukraine? If so, what should Ukraine and the West do about it?

The decline is obvious. Russia’s economy has been completely stagnant since 2014 (and mostly stagnant since 2009), and Putin has made clear that he has no interest in delivering economic growth or improved living standards. In US dollar terms, Russia’s GDP fell from $2.3 trillion in 2013 to $1.5 trillion in 2020. Since Putin first invaded Ukraine and illegally annexed Crimea in 2014, Russian households’ real (inflation-adjusted) disposable income has fallen by 10%.

With nothing good to say about the economy, Putin has touted Russia’s large international currency reserves and minimal public debt. These statistics appear to support his pursuit of national “greatness,” which has become synonymous with his own strongman rule.

Putin thus aspires to create a modern-day Sparta – a state focused solely on its military prowess. Since Russia’s August 2008 attack on Georgia, which revealed major military shortcomings, the Kremlin has undertaken substantial military modernization, while much of the rest of Europe has continued its post-Cold War disarmament.

But Russia’s relative military might probably has already peaked. According to the Stockholm International Peace Research Institute, Russian military expenditures reached $62 billion in 2020, a year when US military expenditures were $778 billion and China’s were $252 billion. Even India surpassed Russia with its $73 billion military budget.

Seeing the writing on the wall, Putin may now be thinking that if Russia is going to benefit from its military strength, it had better flex its muscles now, before the country’s economic foundation erodes further. Moreover, this year’s commodity price boom (particularly in energy and metals) has strengthened the Kremlin’s incentive to strike while the iron is hot.

Like a cornered animal, declining powers are often the most dangerous ones. As Graham Allison of Harvard University reminds us in Destined for War, it was a declining power, Austria-Hungary, that started World War I by declaring war on Serbia. In the current context, the Russians appear to be planning a tank and artillery campaign reminiscent of World War II; if so, their war machine is as outdated as Putin’s view of Ukraine.

A contemporary, peace-loving Western reader might wonder why Putin would want to start a war. Surely he is familiar with the legacy of Vyacheslav von Plehve, the Russian interior minister who, in 1904, famously argued that, “To avert a revolution, we need a small, victorious war!” Soon thereafter, von Plehve was assassinated by a revolutionary. Even so, the 1904-05 Russo-Japanese War ensued. That conflict was neither small nor victorious – and it ended up catalyzing the revolution of 1905.

Putin is most likely focused more on his own small, successful wars in Georgia in 2008 and Crimea in 2014, which led to his highest approval ratings ever. Since then, his approval has reached new lows, and with public discontent building, he has ratcheted up political repression to a level not seen since his hero, the late Soviet leader Yuri Andropov, was in power (1982-84).

To justify his increasingly extreme repression, Putin has cranked up the Kremlin’s propaganda machinery to Soviet levels. But anti-Western messaging will not persuade the population to support him. For that, he needs another highly successful war. And because Russia stands no chance in a big war against the whole West, it needs a much more limited conflict. Hence, Putin’s choice of Ukraine, which he calls a Western vassal.

But a small, victorious war is not possible in Ukraine, either. As Ukraine’s new defense minister, Oleksiy Reznikov, recently pointed out:

“The human cost for Ukraine would be catastrophic, but Ukrainians would not mourn alone. Russia would also suffer massive losses. Images of coffins returning to Russia from the front lines in Ukraine would spread like a virus across social media and would soon prove too much for even the Kremlin censors to contain. A major war in Ukraine would plunge the whole of Europe into crisis.”

US intelligence agencies warn that Russia is mobilizing some 175,000 troops near its border with Ukraine. But a force of that size would not suffice. Ukraine’s active military forces comprise 250,000 troops, many with ample battle experience, who would be defending their homeland against soldiers who may have no higher aim than collecting their salaries.

Russia’s mistake in 1904 was that it did not take Japan seriously as a military power. When Japan emerged victorious, the Czar’s power was fatally weakened, allowing for the revolution that followed. A 2022 Russo-Ukrainian war could prove to be an even bigger folly, one that Putin is unlikely to survive.

In the meantime, the Kremlin must not be allowed to benefit domestically from its saber-rattling. The West responded with only limited sanctions following Putin’s previous aggression against Georgia and Ukraine. It must learn from those mistakes and stand fully with Ukraine. In addition to providing military supplies and training for Ukraine, the West should impose truly devastating sanctions against Russia. Biden and US Secretary of State Antony Blinken have promised as much. They and America’s European allies now must follow through.

NEW YORK – In recent months, Russia has positioned a large and capable military force along its border with Ukraine. What we do not know is why (capabilities are always easier to gauge than intentions), or even if Russian President Vladimir Putin has decided on a course of action. Thus far, he has created options, not outcomes.

What comes to mind is July 1990, when another autocrat, Saddam Hussein, positioned sizable military forces along Iraq’s southern border with Kuwait. Then, as now, intentions were murky but the imbalance of forces was obvious. Arab leaders told then-US President George H.W. Bush not to overreact, convinced it was a ploy to compel Kuwait to take steps to increase the price of oil, which would help Iraq recover and rearm after its long war with Iran.

By early August, though, what to many had looked like political theater had become all too real. Invasion led to conquest, and it took a massive international coalition led by the United States to oust Iraqi forces from Kuwait and restore the country’s sovereignty.

Could a similar dynamic be playing out today on the Russia-Ukraine border?

US President Joe Biden’s administration has reacted to Russia’s troop buildup with a mix of honey and vinegar. The objective is to persuade Russia not to invade by making clear that the costs would outweigh any benefits and that some Russian concerns could be addressed, at least in part, if it backed off. Call it deterrence mixed with diplomacy.

Some have criticized the US response as too weak. But geography and military balance make direct defense of Ukraine all but impossible. Biden was right to take direct US military intervention off the table: not acting on such a threat would only reinforce mounting doubts as to America’s reliability.

But Biden is also right to push back against Russia. The US and the United Kingdom, along with Russia itself, provided assurances to Ukraine in 1994 that, in exchange for giving up the nuclear arsenal it had inherited from the Soviet Union, its sovereignty and borders would be respected. This did not constitute a NATO-like security commitment, but it did imply that Ukraine would not be abandoned.

And yet some who oppose direct resistance of Russian aggression against Ukraine support it in the case of possible Chinese aggression against Taiwan. In both instances, geography works against US military options, and in neither is the US bound by an ironclad security commitment. But in the case of Ukraine, NATO allies are not prepared to defend against a Russian attack and are not expecting the US to do so. By contrast, US allies and partners are prepared to resist Chinese aggression and expect that the US would help frustrate any Chinese bid for regional hegemony.

This does not mean Russia should have a free hand versus Ukraine. Whatever order does exist in the world is premised on the principle that no country is permitted to invade another and change borders by force. This more than justifies providing Ukraine with arms to defend itself, as well as threatening to impose severe economic sanctions that would exact a significant cost on Russia’s already fragile, energy-dependent economy.

Biden is also right to offer a diplomatic path for Putin if he decides it would be wiser to walk back from the brink. Several worthy ideas have been suggested: stepped-up US diplomatic participation in the Minsk diplomatic process initiated in the wake of Russia’s intervention in eastern Ukraine in 2014, a mutual pull-back of Russian and Ukrainian forces from their shared border, and a willingness to discuss with Russia the architecture of European security.

The Biden administration is also right to limit what it offers to Putin. It is one thing not to bring Ukraine into NATO now; it would be quite another to rule it out permanently. The same holds for any assurances that might be extended to Russia about other NATO policies. Diplomacy should never be confused with capitulation.

At the end of the day, what comes next is Putin’s decision to make. He sees Ukraine as an organic part of greater Russia, and may well seek its incorporation to cement his legacy and reverse – at least partly – the collapse of the Soviet Union, which he described in 2005 as “a major geopolitical disaster of the century.” One hopes that a policy of raising the costs of invading and offering some face-saving gestures will convince Putin to defuse the crisis he has created.

If, however, deterrence fails and Putin does invade, promised sanctions will have to be introduced. That includes scrapping the Russia-to-Germany Nord Stream 2 gas pipeline and imposing real costs on Russian financial institutions and Putin’s inner circle. It would be a moment, too, to strengthen NATO and provide Ukraine with additional arms, advice, and intelligence.

This brings me back to Iraq, but now in 2003 and the following years. The US invaded out of a concern that Saddam was hiding weapons of mass destruction and because it saw an opportunity to spread democracy, not just to Iraq but throughout the Arab world. But while the war began with a massive “shock and awe” air campaign and the rapid fall of Baghdad, consolidating military advances proved to be both difficult and costly as urban-based groups provided stiff opposition to US-led troops. The American people turned against the war and a foreign policy judged to be overly ambitious and enormously expensive.

A similar fate could await Russia should its troops march on Kyiv and try to control most or all of Ukraine. Here, too, consolidating control in the face of widespread, heavily-armed resistance could prove extremely difficult. Large numbers of Russian soldiers would return home in body bags as they did from Afghanistan following the 1979 Soviet intervention. A decade later, Soviet troops were gone from that country, as were the Soviet leaders associated with the invasion. The Soviet Union itself disintegrated. Putin would be wise to reckon with the lessons of this past before deciding on the future.

WASHINGTON, DC – During his annual press conference on December 23, Russian President Vladimir Putin railed against NATO enlargement. “How would the US react if we delivered rockets near their borders with Canada or Mexico?” he pointedly asked.

Putin’s increasingly combative rhetoric, coupled with Russia’s huge troop buildup on its border with Ukraine, suggests that the Kremlin is readying an invasion to pull the country back into Russia’s sphere of influence and prevent its accession to NATO. Europe could well be heading toward its deadliest interstate conflict since World War II.

But war is hardly foreordained, given the costs that Russia could face if it invaded its neighbor. Although Ukraine’s military forces are still no match for Russia’s, they would be far better at defending the country than they were in 2014, when Russia grabbed Crimea and intervened in the eastern Donbas region to support pro-Russian separatists. Russian aggression has alienated most Ukrainians, making widespread popular resistance likely if Russia tries to seize a major chunk of the country. Putin can expect not only heavy Russian casualties, but also the severe economic sanctions that the United States and its European allies are currently weighing.

With Russia facing such clear downsides if it opts for war, diplomacy has a reasonable chance of averting conflict. Indeed, Moscow recently released a detailed agenda for broad negotiations over European security. Even though many of Russia’s proposals are non-starters, the US and its European partners appear ready to engage, with the US hinting that talks with the Kremlin could begin early next year. In preparation, the Western allies should identify a combination of carrots and sticks that will increase the appeal of a diplomatic route to de-escalation while raising the prospective costs if Putin chooses war.

As for the carrots, NATO should reassure the Kremlin that it is not about to integrate Ukraine or turn the country into a forward outpost of the West’s best weaponry. Although Russia’s aggression against and coercion of its neighbor is unacceptable, its concern about a militarized Ukraine entering NATO is understandable. Major powers don’t like it when other major powers show up on their doorstep.

Even so, US President Joe Biden and his NATO counterparts are right to reject Putin’s demand for a guarantee that NATO will not offer membership to Ukraine. After all, one of the alliance’s core principles is that sovereign countries should be free to choose their geopolitical alignments.

In practice, however, NATO membership for Ukraine is not in the cards. Admitting it would not only provoke Russia, but also saddle the alliance with defending a nation that has a 1,500-mile (2,414-kilometer) border with Russia. Biden has already made clear that “school’s out” regarding Ukraine’s potential NATO membership and that sending US combat troops to the country is “not on the table.”

That reality creates a diplomatic opening. With admission to NATO requiring the consent of all members, Biden can credibly reassure Putin that membership for Ukraine is not up for consideration. And NATO members can provide assurances that they would put quantitative and qualitative limits on the weaponry they provide to Ukraine. Meanwhile, the alliance can, at least in theory, stand by its open-door policy. Such understandings may fall short of Putin’s demand for a codified guarantee, but they should be sufficient to ease his fears that Ukraine will become a NATO garrison on Russia’s southern frontier.

The US should also lead efforts to implement the Minsk Agreements – a roadmap negotiated in 2014 and 2015 to end Russia’s intervention in Donbas. That deal envisaged Ukraine granting a measure of regional autonomy to areas now controlled by Russian-backed separatists. In return, Russia would stop its proxy war, and Ukraine would regain control of Donbas.

Despite the best efforts of France and Germany, which helped to broker the Minsk deal, implementation has gone nowhere, as both Ukraine and Russia have dragged their feet. Washington should now team up with Paris and Berlin to push the Minsk process forward. While the West and Russia will probably have to agree to disagree about Russia’s illegal annexation of Crimea, the Minsk framework holds the promise of ending the conflict in eastern Ukraine, which has claimed well over 10,000 lives.

Should the Kremlin fulfill its Minsk obligations, the Western allies would scale back the economic sanctions imposed since 2014. And as they lean on Ukraine to uphold its Minsk commitments, they should also press the government in Kyiv to implement anti-corruption measures. Ukraine’s long-run welfare depends not just on ending Russian aggression, but also on reining in its oligarchs and cleaning up its politics.

Finally, NATO allies should capitalize on Russia’s offer to discuss broader issues of European security. Russia’s widening rift with the West has pushed it much closer to China, creating a coupling that emboldens both Putin and Chinese President Xi Jinping. But Russia is the junior partner and must be silently uncomfortable with China’s growing power and ambition, which provides the US and Europe with an opportunity to pull Russia westward. The Kremlin needs to know that improving its relations with the West is an option – provided it stops its predatory behavior toward Ukraine and its troublemaking farther afield.

At the same time that it pursues this diplomatic plan, the West needs to signal its readiness to impose punishing economic sanctions if Russian forces enter Ukraine. On the agenda are excluding Russia from the SWIFT international payments system, sanctioning major Russian banks, scrapping the Nord Stream 2 Russia-Germany gas pipeline, and targeting oligarchs in Putin’s inner circle.

NATO allies should also make clear that they are ready to reinforce their eastern frontier and help arm the Ukrainian resistance if Russia invades. Putin tends to pick fights that he can win at relatively low cost. He needs to know that invading Ukraine would be hugely expensive.

The US needs to lead a determined NATO effort to give diplomacy a chance, while readying severe sanctions if diplomacy fails. That approach offers the best way to avert a conflict that would produce no winners.

CAMBRIDGE – As Russia masses troops along its border with Ukraine, fears of an invasion are mounting. The United States has warned that Russia would pay a heavy price, exacted first and foremost through economic sanctions. But President Joe Biden has also declared that he would not send military personnel to defend Ukraine. It is the right approach.

On one hand, the threat of economic sanctions – in particular, exclusion of Russia from the SWIFT international payments system and cancellation of the Nord Stream 2 gas pipeline to Germany – might be enough to deter Russian President Vladimir Putin. On the other hand, any threat that the US and its allies would intervene with troops would not be believable – inviting Putin to call the West’s bluff.

But if Americans and Europeans are unprepared to send troops to Ukraine, why did Western leaders in 2008 promise eventual NATO membership to Ukraine, as well as to Georgia? After all, Article 5 of the North Atlantic Treaty declares that an armed attack against one NATO ally is effectively an attack against all of them. And yet nobody was prepared to come to Georgia’s defense when Russia invaded in 2008, or to Ukraine’s defense when Russia annexed Crimea in 2014. Nor has the West done anything to stop Russia from occupying Ukraine’s eastern Donbas region. Against this background, talk about Ukraine joining NATO has merely provoked Putin, while undermining the West’s credibility.

This reflects a broader problem with US foreign policy since the end of World War II: a poor match between the signals it sends and what it is subsequently able to carry out.

For starters, the US has often overstated its resolve in military engagements. For example, in Vietnam and Afghanistan, it failed to achieve its goals and eventually decided to cut its losses. The speedy collapse of the US-backed governments in Saigon and Kabul showed just how little progress had been made – and dealt heavy blows to America’s global reputation.

This is exactly what then-National Security Adviser Henry Kissinger feared in 1969, when he told French President Charles de Gaulle that a “sudden withdrawal” from Vietnam might create a “credibility problem.” But America lost far more credibility when it withdrew its troops four years later, after spending much more blood and treasure. In both Vietnam and Afghanistan, the US should have left sooner – or never intervened at all.

America’s intervention in Lebanon was blighted by a similar mistake. A multinational force, including hundreds of US soldiers, arrived in August 1982, in order to oversee the Palestine Liberation Organization’s withdrawal from the country. By early September, that mission was complete, and US troops left.

But a massacre of Palestinian refugees by a Christian militia brought Western troops back to Lebanon, where they remained with a far hazier mission. In October 1983, Lebanese terrorists drove a truck full of explosives into the US Marine barracks in Beirut, killing 241 American military personnel. (Meanwhile, a separate attack killed 58 French paratroopers.) The US and its allies withdrew their troops in a matter of months.

Some have argued that the withdrawal was a mistake in that it sent a message to America’s enemies, such as Osama bin Laden, that the US was a “paper tiger.” This is the wrong lesson. In fact, US President Ronald Reagan should have quietly disengaged once the original mission was complete. Like Kissinger, he worried that doing so would damage America’s credibility. Even after the bombing, he repeated vows to keep US forces in Lebanon. But, as in Vietnam and Afghanistan, this served only to compound the reputational blow dealt by the subsequent withdrawal.

The lesson is clear: the US should ensure that any declaration of a willingness to use military force corresponds with what a leader can actually deliver. And this means more than not overstating one’s commitment. Understating it is also a strategic blunder. After all, a credible threat from a military power like the US can act as a powerful deterrent.

The US has, at times, failed to take advantage of this reality. On January 12, 1950, Secretary of State Dean Acheson defined America’s defense perimeter in Asia, but did not include the Korean Peninsula. Six months later, North Korea invaded South Korea – and the US led a United Nations command to defend the country. That command ultimately restored the line dividing the peninsula, but only after three years of fighting and more than 1.7 million casualties. While it is impossible to know whether a credible threat of US intervention would have averted the invasion, it seems unlikely that such a threat would not have affected North Korea’s calculations.

The same goes for Iraqi leader Saddam Hussein’s decision to invade Kuwait in August 1990. Just a few days before the invasion, with Iraqi forces already gathering on the border, the US sent signals that it would not respond militarily.

To be sure, three days after the invasion, US President George H.W. Bush declared, “This will not stand.” And in January 1991, after a series of failed negotiations with Iraq, the US made good on that pledge, leading a 35-country coalition in a massive military assault that drove Saddam’s forces out of Kuwait in a matter of weeks. But with more advance warning, Saddam might not have sent them in the first place.

One successful US intervention characterized by consistency between word and deed unfolded in 1999. President Bill Clinton warned Yugoslavia’s leader, Slobodan Milošević, to withdraw Serbian security forces from Kosovo. When he refused, NATO launched a bombing campaign. Serbian forces agreed to withdraw, and the Serbian people forced Milošević from office the following year.

During the Cold War, US President Richard Nixon saw benefits in being viewed as an irrational and volatile leader, in an effort to deter any provocations. But the so-called madman theory has strict limits, especially for a hegemon and its allies. Ensuring consistency between signals and actions is much more likely to deter conflict, not least by boosting long-term credibility.