The Ukraine crisis has demonstrated that one person alone can endanger world peace. But that one person might not be Russian President Vladimir Putin, who in reality only leads a large regional power that, owing to his authoritarian rule and muddled economics, is a long-term threat more to itself than to the world.

No, the lone actor most responsible for threatening world peace might unwittingly be U.S. President Barack Obama, with his scholarly inertia and apparent disregard for the fate of smaller, faraway countries.

Of course, Obama is not responsible for Russia’s invasion and annexation of Crimea, or for Putin’s massing of Russian troops on Ukraine’s eastern border in an effort to intimidate the government in Kiev. Nor is Obama alone in crafting a Western policy of appeasement by default. German Chancellor Angela Merkel also bears considerable responsibility: Her tough rhetoric masks a largely business-as-usual approach that reflects her country’s dependence on Russian gas supplies.

But Obama is responsible for his administration’s apparent indifference to the fate of the American-built order that has governed world affairs since the end of World War II. Unless he toughens his policies, the rules and norms that have guaranteed peace for so many for so long could lose their force.

The utter disconnect between America’s diplomatic principles and practice has become so great that it is emboldening the country’s adversaries.

That is why, following Russia’s illegal seizure and annexation of Crimea, Putin is now trying to mold Ukraine’s eastern provinces into vassal regions, if not foment irredentism, to realize his dream of reconstituting the Russian empire.

But it is not only America’s rivals who are taking note of Obama’s passivity. The United States’ closest allies are also watching nervously, and the conclusions they appear to be drawing could harm its national security interests severely in the years and decades to come.

Consider the Middle East, where Saudi Arabia is already openly questioning the reliability of the Kingdom’s historic U.S. defense guarantee. And U.S. Secretary of State John Kerry’s “guidance” for a settlement of the Israeli-Palestinian conflict, which should have been unveiled this month, will now remain under wraps. Speculation abounded that Kerry’s proposal would contain a specific U.S. guarantee of Israel’s borders. But can anyone imagine Israelis taking America at its word after watching the U.S. dither while Russia redrew the map of Ukraine?

In the Budapest Memorandum of 1994, the U.S., together with the United Kingdom and Russia, guaranteed Ukraine’s territorial integrity in exchange for its surrender of the large nuclear arsenal it inherited from the Soviet Union. Now that the U.S. has disregarded its obligation to Ukraine — reportedly unwilling even to share intelligence with its government on Russian troop movements, much less supply the country with the means to defend itself — all bets are off concerning an American guarantee of Israel’s security and territorial integrity.

For that matter, why should Iran discontinue its nuclear program when it sees the ease with which Ukraine was dismembered? After all, the Iranians have borne far harsher sanctions than those imposed on Russia so far.

By acquiescing in Russia’s seizure of Crimea, the U.S. may also see core alliances begin to unravel. For example, the U.S. has openly stated that it will defend Japan should China forcibly seize the disputed Senkaku Islands.

But if America can evade its guarantee of Ukraine’s territorial integrity, why should Japan’s leaders believe that the U.S. will do otherwise in the case of a far-flung cluster of uninhabited islands that are scarcely more than rocks inhabited by sheep?

U.S. Secretary of Defense Chuck Hagel heard an earful of official doubt about the credibility of America’s defense commitment during his recent visit to Japan.

It’s certain that Obama heard more of the same in Tokyo this week.

Of course, the U.S. is no longer in a position to “pay any price … to secure the survival and the success of liberty,” as John F. Kennedy put it in his inaugural address — not in Ukraine, and not anywhere else. The huge price of its wars in Afghanistan and Iraq has understandably made the U.S. war-weary.

Moreover, no country has the right to expect Americans to fight and die on its territory for its freedom. But has the U.S. become so withdrawn from the world that it is willing to pay only a symbolic price, such as that implied by Russia’s tit-for-tat sanctions, to stop aggression that threatens the international order?

Have America’s recent foreign wars so scarred its leaders that they are unable to defend the world order that their predecessors created and for which many Americans have died?

The time is growing short for the U.S. to demonstrate anew — to friend and foe — that its word remains its bond. Unless Russia honors the accord recently reached in Geneva to defuse the Ukraine crisis, the U.S. must use — and soon — its full arsenal of nonmilitary means to demonstrate to Putin the costs of his 1930s-style revanchism.

The soft underbelly of Putin’s imperial ambitions is Russia’s brittle and undiversified economy, and the expectations of ordinary Russians for improved living standards. The U.S. and the European Union need to demonstrate clearly to the Russian people that their president’s policies will mean a likely return to the poverty and tyranny of the Soviet era. Any lesser display of resolve may fatally weaken the bedrock of Western security — and that of the world.

Yuriko Koike, Japan’s former defense minister and national security adviser, is a member of the Lower House. © 2014 Project Syndicate

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