As America's political pundits have struggled to make sense of Donald Trump's improbable rise to the head of the Republican pack, it's become commonplace to hear him described as an ideological moderate. Sure, some of his proposals — the wall along the Mexican border and mass deportations; the ban on permitting Muslims to enter the United States — are extreme. And yes, his violence-intoxicated, trash-talking misogynistic cult of personality sometimes points in a fascistic direction. But on a range of issues that typically define a politician's place on the ideological spectrum — taxes, spending, using government to help American workers, social issues — Trump can sound like a centrist.

I've been skeptical of this line from the beginning, but now that Trump has talked at some length about foreign policy with The Washington Post and The New York Times, there can be little doubt that Trump is a bona fide radical — a candidate who intends nothing less than to dismantle the core institutions of the postwar liberal international order and to break dramatically from the policies and principles that have sustained it for the better part of the past 70 years.

We don't yet know whether Trump voters support him in part because of his foreign policy extremism or despite it. But the very fact that he's done as well as he has while pushing such a radical agenda is likely to inspire copycat candidates in future elections. Is it possible that the greatest impact of Trump's presidential run will be to inject an amoral unilateralism into the political mainstream?

That prospect should be more than enough to send chills down the spines of thoughtful and historically informed citizens.

Until recently, discussion of foreign policy among this election's Republican presidential candidates swung between two poles. On one end was the bellicose internationalism (or neoconservatism) that has prevailed in the GOP since the Sept. 11 attacks. Its greatest champions in the race were Marco Rubio and Jeb Bush, though several of the other candidates embraced variations on the position.

At the opposite pole are Trump and Ted Cruz, who have positioned themselves as "to hell with 'em hawks." (The phrase was coined by John Derbyshire in 2006 and recently revived by Noah Millman.) If neocons tend to presume that American militarism is invariably good for the U.S. and the world, "to hell with 'em hawks" care only about pursuing American interests and appear willing and eager to use American military might to punish our enemies, often severely and perhaps even in contravention of international law and just-war restraints. (Trump's full-throated endorsement of torture is one example; Cruz's fondness for "carpet bombing" ISIS is another.)

But now Trump has gone several steps beyond the basic "to hell with 'em hawk" position. In his remarks to the Post and the Times, Trump claims that the liberal order created by the United States after World War II as a way of keeping a lid on global conflict has left us a "poor country" that's been "disrespected, mocked, and ripped off for many, many years by people who were smarter, shrewder, tougher."

In Trump's view, the North Atlantic Treaty Organization is "obsolete," and so are American alliances in Asia. Nuclear non-proliferation should be abandoned in favor of encouraging Japan and South Korea to develop and deploy their own nukes. Saudi Arabia should foot the bill for American protection or face disintegration as a state. The Iran nuclear deal should be renegotiated, not because of geopolitical considerations, but because the Iranian government is currently free to use money acquired through the lifting of international sanctions to purchase aircraft from Airbus, a European company, and forbidden from doing business with Boeing. (Remaining sanctions on Tehran forbid American companies from trading with or investing in the country.)

Trump calls this, unironically, a foreign policy of "America First." It's possible that he's unaware that the term has a history going back to the isolationist movement led by Charles Lindbergh in the years leading up to the Second World War.

But Trump's critics shouldn't push the parallel too hard. What Trump is proposing can't really be described as isolationist — at least if the term means the act of withdrawing behind the safety of our borders and protective oceans. That's classic American isolationism, which traces its lineage back to John Quincy Adams. Ron Paul ran on a version of it in his quixotic 2008 and 2012 presidential campaigns, and his son Rand Paul proposed a very mild version of it in his own unsuccessful bid for the White House in 2016.

Trump's vision of American foreign policy is very different. It would shred the reigning (though weakening) liberal order in favor of a world in which the United States goes its own way, cutting one-off deals with countries around the globe, doing whatever it wants and feels it needs to do to defend itself or further its economic advantage.

This isn't isolationist in the sense that it favors the U.S. exiting the world stage, turning inward, and tending its own garden while the rest of the globe goes to hell behind its back. On the contrary, Trump seems to be suggesting that, if anything, we need to be more active and aggressive in the world than we are. We need to throw our weight around, flex our muscles, cut our allies lose, obliterate our enemies, cut deals with our adversaries, consolidate our position, and reduce our obligations and exposure around the world.

In the seven decades since 1945, the U.S. came closest to adopting such an attitude in the months leading up to the 2003 Iraq War. That's when the administration of George W. Bush and its cheerleaders in the media toyed with dismissing the liberal order (including the United Nations) in favor of a highly moralized policy of America going it alone. We would do what we thought was best for America and the world, even if most of the nations of the world didn't approve.

It didn't last. As the exhilaration of the Iraq invasion gave way to the morass of the occupation and insurgency, the U.S. recommitted itself to working in concert with allies and to seeking international consensus in responding to global crises. That was the norm before, and it's been the norm since.

Trump would move us back permanently to the exceptional winter of 2003, albeit without the moralism.

Are a plurality of Americans prepared to embrace a foreign policy of amoral unilateralism?

The 2016 presidential election will be about many things. But it will also, and perhaps most pressingly, be about that.