Editor's note: Frida Ghitis is a world affairs columnist for The Miami Herald and World Politics Review. A former CNN producer and correspondent, she is the author of "The End of Revolution: A Changing World in the Age of Live Television." Follow her on Twitter @FridaGhitis.
(CNN) -- In the years since President Barack Obama moved into the White House, Western influence on the global stage has declined. With Russian troops massing on Ukraine's borders and NATO's top commander warning that Russian President Vladimir Putin may be preparing to make another move after annexing Crimea, there is an urgent priority.
President Obama has arrived in Europe at what could turn out to be a hinge point in history. It is crucial that he use this fraught occasion to launch a strategy to reinvigorate the Atlantic alliance, reassure its friends and put its enemies on notice.
Obama and other Western leaders called for Syria's Bashar al-Assad to step down, yet he has arguably grown stronger since then. The government of Egypt, once a close ally of the West, has spun away. Russia blatantly ignored American and European calls not to invade Ukrainian territory. The U.S. has surprisingly little influence even in Afghanistan, where it still has thousands of troops.
The loss of American and European influence is not just a loss of geopolitical clout for one bloc. The West stands for many of the principles that the world has consecrated as universal, such as rule of law, respect for international norms and the protection of human rights.
The United States and its European allies possess a triple arsenal of enormous power.
First, they embody ideals that hold powerful universal appeal. Second, their combined economies, despite the recent downturn, easily dwarf any and all of their rivals. Third, the U.S. and its allies remain the undisputed top military power on Earth.
Obama must launch a program to re-energize the partnership of the democratic West, brandishing the unity of the alliance and the universality of the principles it espouses.
No, Europe and the U.S. have not behaved in perfect accordance with those principles, but their institutions and laws, however flawed, still aim for governments that derive power not from corruption, force or manipulation but from the will of the people. It's a system in which individuals are solemnly respected by the state and where laws are fairly made and justly applied to all people, including those who disagree with the government.
The decline of the West's relative power means that the forces that strive for these norms have grown weaker. It means there is less strength to prevent or reverse ongoing catastrophes, such as the war in Syria or the infamy that unfolds every day in North Korea.
It means Putin, whose rule is increasingly authoritarian at home, has found it possible to move without worry and cross what were international borders until just a few days ago, violating not only international law but also an agreement signed by Moscow in 1994 vowing to respect Ukraine's borders. The weaker West has allowed Putin to fearlessly flaunt his disdain for any pushback from the international community while his heavily armed forces bare their teeth across the eastern side of Ukraine's border, and from the south, from within what used to be Ukraine's Crimea.
And he had no reason to fear that the West would do much to stop it.
Obama's response to Putin's actions in Ukraine has gradually taken on a more credible character. The latest round of sanctions, announced on Friday, bites a little closer to Putin's inner circle. The real test is now, when he is meeting with allies in Europe. The decision to expel Russia from the G-8 would constitute a dramatic and important symbolic move.
Putin will dismiss every decision with bravado. The move not to hold the next G8 summit in his shining Sochi, rebuilt at enormous cost for his showcase Winter Olympics, has to sting.
Russians, many of whom had grown disenchanted with Putin, have nevertheless rallied around their strutting President. An upsurge in a leader's popularity, however, is common in situations like these. Russians don't want their country to become an international pariah. Eventually, some will see that what is happening is clearly not, as Putin describes, the result of an aggressive America or of a West that seeks to diminish and humiliate Russia.
Putin's closest associates, the men who have enriched themselves in his autocratic system, will swear their support. But they want access to global markets and they want the prestige of rubbing elbows with global elites. They see themselves as successful, worldly and sophisticated businessmen. They don't want the world to perceive them as outlaw cronies in an isolated regime.
Putin's actions have a thin silver lining. They may just help awaken the West from its depressive slumber and shake the U.S. from the conceit that it can pay less attention to the rest of the world without consequences.
The past few years have been painful for Europe and for the U.S. and have eroded the relationship. Friction between the two sides of the Atlantic blurred the strong ties that still bind the allies. Europe, still struggling with a deep recession, is having a case of low self-esteem. And Americans, too, for good reason, are not feeling particularly proud of their democratic institutions.
And yet, the protesters who occupied the square in Ukraine's capital yearn for a system that resembles what they see from their European neighbors, particularly the ones in Eastern Europe, which were once under Moscow's domination.
Obama must revitalize the alliance. Remind its members and the world what it stands for and just how much it can do. Help end European reliance on Russia fuel. Convince London and Paris and Berlin that they can do without the oligarchs' cash.
He must schedule frequent, high-profile working meetings to take steps to isolate Russia and clarify what the West seeks -- not domination of Russia's neighborhood, but a system of prosperity and democracy that benefits every country, including Russia, if it chooses to play by the rules. And countries that mass their troops, threatening to invade their neighbors, must pay a high price, a price that will escalate if they make another move.
Then the West's influence in the global stage may just reverse course, and that will be bad news for the world's worst regimes. It's a long game, but that is the priority right now.
The opinions expressed in this commentary are solely those of Frida Ghitis.