Conservatives have long embraced the concept of American exceptionalism. Ronald Reagan often implied that America was uniquely blessed by God, citing a World War II-era quote from the Pope that "into the hands of America, God has placed the destinies of afflicted humanity." His vice president, George H. W. Bush, put it less eloquently when he said, "I will never apologize for the United States of America, ever. I don't care what the facts are."

This theocratic, jingoistic version of American exceptionalism has long rubbed the Left the wrong way. Liberals bristled as conservatives used patriotism to club those who criticized America's actions abroad. More recently, liberal eyes rolled as conservatives tried to use that bludgeon on President Obama, just because he sought to rehabilitate America's moral authority by acknowledging those instances when America did not live up to its ideals.

But with Russia's undemocratic, imperialist impulses now laid bare in Crimea, it's time for liberals to reconsider how exceptional American has been, and why it matters for the good of the world.

Sure, America has not been singled out by God as better than other countries. Yes, America has been falling short of its own ideals from the get-go with the embrace of slavery, the forced relocation of Native Americans, the internment of Japanese Americans in World War II, and the propping up of various dictators, to name just a few transgressions.

But here's the thing: America still has ideals. Russia does not.

Because of our ideals, when the rise of American power coincided with a more interconnected world, America made the unique choice to promote the global interest and not the self-interest. If we had kept our ideals to ourselves, and retreated to isolation between the two oceans, the world would be less free today.

In 1917, when Germany goaded Woodrow Wilson into entering World War I, Wilson declared, "The world must be made safe for democracy... We have no selfish ends to serve. We desire no conquest, no dominion." He later made "self-determination" and the "impartial adjustment of colonial claims" a key principle for any peace agreement. Wilson's groundbreaking stance was greeted with much resistance from our allies, and the compromises Wilson was compelled to accept contributed to the demise of the treaty and the League of Nations in the United States Senate.

Nevertheless, Wilson set a north star that would guide Franklin Roosevelt and Harry Truman in their successful quest to validate their predecessor's vision. Their administrations played the quintessential role in not only forming the United Nations, but also — as explained by U.N. historian Stephen Schlesinger — establishing in the charter a decolonization process over the objections of our allies. As a result, the U.N. sparked a wave of decolonization and independence, nearly quadrupling the number of countries in the world.

Meanwhile, the Soviet Union under Josef Stalin treated the end of World War II as an opportunity to claim spoils and occupy territory, not to promote freedom.

Where would the world be if America did not assert its democratic values on the world stage during the last century? And where will the world go if we do not do so now?

The Russia of today is less brutal — Putin is no mass murderer like Stalin. But the old Soviet Union did preach a value, namely communism, to justify its existence. Communism may be abhorrent either in its nature or in practice, but it was a value nonetheless.

Putin's Russia doesn't even offer a value for the world to consider. His geopolitical aim to is create a multinational "Eurasian Union" to limit the influence of America and Europe in its region. As explained by the Boston Globe's Leon Neyfakh, Putin has yet to offer an "ideological glue to hold it together." Neyfakh argues that it's "opaque" whether Putin's dream is rooted in a "raw appetite for power and drive for a stronger Russia." But without a stated value, what else is there? And what would entice a country to choose this cold, soulless union if it is only to serve Putin's ends?

In fact, few are. Only Belarus and Kazakhstan have joined the union, and Neyfakh speculates that both may be reconsidering after being "spooked" by Putin's Crimea power play. While Putin likely sees all of Ukraine as a "necessary anchor" for his plans, he can't get it to come on its own free will. But for an American foreign policy driven by a sense of exceptionalism, Putin may have swallowed all of Ukraine by now.

Embracing American exceptionalism does not mean embracing a delusion of American omnipotence. Having altruistic ideals is not a magic sauce that can win any military confrontation and forge any treaty. Plenty of debate can and should be had regarding how America can best exert global influence. But a world without ideals is a world where only the power-hungry roam free. America is the country that brought those ideals to the world during the last 100 years, and we forget that at our peril.