President Trump is casually challenging one of the core ideas put forward by many ideological conservatives: that America is exceptional, and that when it ventures out into the world it does so with a uniquely benevolent nature.

In an interview that aired before the Super Bowl, Fox News' Bill O'Reilly noted to Trump that "Putin is a killer." Trump responded with the world weariness of a mafioso. "There are a lot of killers. We have a lot of killers... What, you think our country is so innocent?"

In typical Trump fashion, one of the president's supporters actually expressed this Trumpian idea with more felicity than we can expect from our leader. Last October, Peter Thiel explained that "Trump's agenda is about making America a normal country." For Thiel, Trump was challenging the "dogma of Reaganism" when he "questioned the core concept of American exceptionalism."

But obviously, it's a bigger deal when Trump says it himself. And in the aftermath of this interview, a number of unTrumpified Republicans, like Sens. Ben Sasse and Marco Rubio, criticized the president for the suggested equivalence of the U.S. and Russia. America is a force of unadulterated good, the senators insisted. We're not like those thugs in Russia at all. How dare anyone suggest otherwise.

There's a kind of unreality to this exchange between Trump and his Republican critics. And it highlights the way in which the GOP's understanding of American exceptionalism collapses into a self-deluding sentimentalism, and how the critique of it can likewise collapse into a kind of cynicism — or even nihilism.

Rubio's and Trump's dueling views of America's role in the world are both permissive, but in their own ways. Rubio and other partisans of American exceptionalism trust that America is fundamentally good and benevolent as it engages the world. This belief acts as a kind of moral license for America to intervene. And it led to some of the messianism of our foreign policy after 9/11. America would bring democracy to the Middle East, and rout dictators. America's actions would win hearts and minds. We were a force for goodness in the world.

The Trumpian idea that we are a "normal country" that has a "lot of killers" is permissive in another way. "You think our country is so innocent?" is exactly what a man who intends to bring back "worse than waterboarding" would say to disarm his moralizing critics.

One way around the dilemma presented by these two views is to look to an older form of American exceptionalism — one that recognizes that America is the lucky inheritor of the Anglo-Protestant tradition of common law. It also recognizes that America's liberty is partly guaranteed by America's utterly unique position as a continent-spanning colossus, blessed with incredible natural resources. America has friendly neighbors and giant oceans that separate it from great powers, meaning that it has rarely faced the temptation of militarizing or regimenting its society. It's no accident that Anglo traditions of liberty tend to thrive on islands like the U.K. or continent-sized powers like Australia and America.

America is not innocent or good in some fundamental way. Like most nations, it was founded in expansion and extermination. It was the engine of the Atlantic slave trade. And it has committed barbarities in war. If America is innocent in any way, it is in the sense of its ignorance and absentmindedness, as in its capacity to believe that regime change can be effected in the Middle East with little cost, creating a democratic domino effect in the region.

None of this makes the American government like Russia's, of course. America's government does not kill journalists and political opponents. It doesn't intervene dramatically in the internal politics of its near neighbors. Why? Partly because America's existing security means it does not have to fear journalists or Canadians undermining our society, tipping us into chaos or disorder.

Now, imagine if we were located in a neighborhood surrounded by pre-WWII Japan, Germany, China, and Turkey. Our people would put up with — or even admire — a much more brutal government than the one we have. Human nature is a constant in America and Russia. But history, culture, geography, and the arrangement of power shape us in profoundly different ways.

You could argue that America's experience of its own liberty really does make it the well-wisher of others. Americans should be happy to point out that this country's post-war investments, financial and ideological, in Western Europe and the NATO alliance were considerably kinder to Western Europeans than anything attempted by Moscow in its Eastern bloc or in the German Democratic Republic. At bottom, the calculation for America was just as much driven by security as was the Russians'. But our security interests really did redound to the benefit of the fallen Western European powers after World War II.

If America wants to preserve its role as a preeminent liberal power, it needs to husband its resources, protect the independence that makes it a liberal power, and understand why and how it is truly exceptional. Don't forget: It was the excess of idealism among our elites, including their moral self-regard and their infatuation with their innocence, that led to America's disillusionment in the Middle East, and ultimately to the presidency of Donald Trump, a man of profoundly illiberal instincts.