This is GPS, the Global Public Square. Welcome to all of you in the United States and around the world.

I'm Farid Zakaria, coming to you live from New York.

Today on the program, Ukraine's capital Keev is under siege.

Putin's military assault has rallied Ukrainians and much of the world against the Russian President.

Will the military challenges plus sanctions cause Putin to reconsider this war?

I'll get the latest from CNN reporters on the ground.

Former Ukrainian President Petro Poroshenko will join us to tell me why he is willing to risk his life to take up arms against Russia.

And I will have an exclusive interview with the former US Secretary of Defense, former CIA director Robert Gates.

But first, here's my take.

Russia's utterly unprovoked, unjustifiable, immoral invasion of Ukraine would seem to mark the end of an era, one that began with the fall of the Berlin Wall in 1989.

In that post-cold war age, Western ideas about politics, economics and culture spread across the world largely uncontested, and American power undergirded the international system.

It was not a period of tranquility, think of the wars in Yugoslavia and the Middle East.

But it was a time in which American power and liberal democracy seemed triumphant, and the international system seemed to work more cooperatively than at any previous point in history.

That back-s-american had began to wane for many reasons, including the rise of countries like China and India, the disasters in Iraq and Afghanistan, the financial and democratic crises in the West.

But the most disruptive force has been, the return of an imperial Russia, determined to recreate a sphere of influence in which it could dominate its neighbors.

For the past decade, Putin's Russia has been the world's great geopolitical spoiler, actively attempting to unravel the rules-based international system.

For many commentators, the current crisis is proof that this system has collapsed and that the democratic age was a brief fantasy.

David Brooks writes that history is reverting toward barbarism. Robert Kagan has said the jungle is growing back.

But is that kind of pessimism justified?

I am more hopeful that within the terrible news of the past few days lies some powerful positive forces.

After all, what caused this crisis in the first place? It's very simple.

The overwhelming desire of Ukrainians to live in an open democratic society.

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