Foreign policy played little role in the 2016 Democratic primary, but 2020 might be different. Most of the field has concentrated so far on domestic questions, with few staking out much in the way of a signature perspective — with one exception: Bernie Sanders. As Peter Beinart writes at The Atlantic, Sanders has elucidated a platform that is strongly critical of America's imperial blundering, arguing instead for a return of neighborly internationalism and re-engagement with the United Nations.

In the democratic socialist tradition, fighting imperialism has usually been a top priority (the vast Soviet empire notwithstanding). Sanders has the most thoroughgoing critique of American empire of any major candidate since George McGovern at least. But it raises the question: Would he be able to roll back the empire from the very pinnacle of imperial power?

In the 2016 race, Sanders inadvertently revealed he didn't have all that much to say about foreign policy, only belatedly developing a perspective (which included a delicious slam on the butchery of Henry Kissinger, to be fair). But he has spent the last two years further developing his foreign policy thinking, notably hiring former Center for American Progress expert Matt Duss (subject of a recent profile in The Nation by David Klion). He gave two big foreign speeches over the last two years outlining his views.

What Sanders would be able to achieve as president depends heavily on the nature of the American empire. In his first speech, he argued that the bloated defense budget was infringing on other national priorities, by eating up money and resources that could be spent at home, and quoted President Eisenhower's famous "A Chance for Peace" and "military-industrial complex" speeches to that effect.

When we consider the last two decades of imperial war and domination (and much before that), the overwhelming impression is one of futility and waste. America has spent something like $6 trillion on just the wars in Afghanistan and Iraq — and for what? It's not like U.S. businesses need those export markets, which have been ruined in any case by all the chaos and violence. Even the oil of Iraq could not possibly compensate for that much spending (for $4 trillion, about the cost of the Iraq War, we could have nearly bought half of Iraq's entire oil reserves outright at going prices). Indeed, with the rise of fracking the U.S. itself has become the world's largest oil producer.

At least when it comes to imperialist war, the last two decades of U.S. foreign policy have been as pointless as they have been gruesome.

That accounts for the odd spectacle of a democratic socialist quoting a moderate conservative president who had previously been the top general in the biggest war in U.S. history. There is quite substantial overlap between a leftist anti-imperialist perspective and the sort of realist conservative view focused on the national interest and avoiding expensive overseas entanglements. That kind of thinking is now largely absent from the American right, of course, with the exception of a few heterodox voices like Daniel Larison, Andrew Bacevich, and the late Rep. Walter Jones (R-N.C.). But remarkably, Sanders did manage to team up with Senator Mike Lee (R-Utah) to pass a bipartisan resolution stopping U.S. support for the Saudi war in Yemen, a second version of which will be up for a Senate vote soon.

However, Sanders also wants to build up a new lefty internationalism. In his speech at SAIS, he called for the creation of an international movement working towards "democracy, egalitarianism, and economic, social, racial, and environmental justice," in order to combat the manifest appearance of "a growing worldwide movement toward authoritarianism, oligarchy, and kleptocracy." As Beinart notes, he has thus been sharply critical of America's various Cold War atrocities in Latin America, Iran, Southeast Asia, and of Israel's treatment of Palestinians in the West Bank and Gaza.

Neither Republicans nor the bipartisan D.C. foreign policy establishment "Blob" will like this one bit. The Blob probably couldn't even be talked around to an Eisenhower-style realist restraint, much less an ambitious pivot away from military spending and towards international diplomacy. Just look at the number of upstanding national security liberals who reacted with spluttering, stunned outrage when Rep. Ilhan Omar (D-Minn.) criticized Elliot Abrams for covering up mass murder as part of the U.S. intervention in El Salvador in the 1980s. In Blob World, U.S. military action is always right by definition, "we" always have to be meddling in most every foreign dispute no matter how badly the last attempt went, Israel is the most important U.S. ally no matter how much it formalizes its apartheid system, and anyone who looks askance at the resulting heaps of corpses is Unserious. This crew is rotten to the bone, both morally and intellectually.

That said, the office of the presidency does have extremely broad authority over foreign policy, and Sanders could achieve a great deal even if he couldn't dismantle the whole imperial structure. Simply having all the carrier battle groups turn donuts in the middle of the Pacific would be a vast improvement on the endless dirty wars and airstrikes across the globe. One concrete place to start would be a deep investigation into the horrendously corrupt military procurement process, which is simply riddled with grifters and incompetence from top to bottom. Cutting out some of the awesome fraud in military contracting would likely deflate the Blob considerably (at the lamentable expense of causing a recession in the northern Virginia hot tub business). Another idea is a ban on foreign lobbying. A key Blob support is oceans of cash from Saudi Arabia, the U.A.E., Israel, and many other countries.

But make no mistake, it will be a terrific battle. If Sanders wants to reform American foreign policy along sane and moral lines, he better be ready for a fight.