For decades, progressive politicians and activists failed to articulate the role the United States should play in the world. Marginalized by the bipartisan devotion to military intervention and global deregulation, the left spent its energy protesting America’s most egregious and bloody actions. But Donald Trump’s departures from years-old geopolitical orthodoxies—even if these deviations have often proved more rhetorical than real—have convinced progressive leaders to rethink American foreign policy. Trump’s refusal to even pretend to care about democracy promotion has shown them that perhaps the electorate is ready to move beyond platitudes about America’s benevolent guardianship.

In just the last few months, the left has begun to complement its flurry of domestic policy proposals with bold, new visions for foreign policy. In early March, Senators Bernie Sanders and Elizabeth Warren and Representatives Ro Khanna, Alexandria Ocasio-Cortez, Ilhan Omar, and Rashida Tlaib signed a pledge, issued by the veterans’ group Common Defense, that calls for the end of the “global, destabilizing, ever-expanding, endless war” that has cost the “blood, lives, [and] dollars” of millions of people around the world. Sanders and Warren, both of whom are running for president, have also issued their own foreign-policy manifestos. In Foreign Affairs—the bible of the foreign-policy establishment—Warren recently insisted that the United States cease its military interventions, reverse the trend toward global deregulation, and encourage domestic redistribution. Sanders, who didn’t even offer a foreign-policy platform in 2016, has also made geopolitics central to his campaign. In a major speech given last October at Johns Hopkins University, he argued that instead of sponsoring wars and the free movement of capital, the United States must lead an “international movement” dedicated to increasing the power of labor and combatting the catastrophic effects of climate change.

After decades of numbing bipartisan fixation with military entanglements, the left has roundly cheered on Warren’s and Sanders’s ideas. In The New York Times, Jamelle Bouie praised Sanders’s “robust” geopolitical vision, while in The Atlantic, Peter Beinart approvingly mused that foreign policy will “distinguish” left-wing Democrats from their centrist counterparts. Trump seems to have done what the Iraq War, Barack Obama’s drone operations, and deployments of US Special Forces abroad could not: jolt left-wing Democrats into offering a genuine alternative to the foreign-policy establishment and its interventionist consensus.

Nevertheless, progressives should be cautious about how Warren and Sanders understand international relations. For all their ingenuity, both candidates sometimes insist that this moment is defined by a battle between good and evil. In doing so, they frame geopolitics in simplistic terms that undermine the left’s long-term goals. According to Sanders, for instance, the world is presently locked in a “struggle” between a “movement toward authoritarianism, oligarchy, and kleptocracy” and a “movement [committed to] strengthening democracy, egalitarianism, and economic, social, racial, and environmental justice.” For this reason, Sanders maintains, the United States must lead a coalition that combats “the rise of a new authoritarian axis” led by Russia’s Vladimir Putin, Brazil’s Jair Bolsonaro, Hungary’s Viktor Orbán, and other right-wing dictators. Warren has also been ominous in her rhetoric, warning that these regimes may weaken the foundations of America’s democratic institutions. The global right’s “marriage of authoritarianism and corrupt capitalism,” she cautioned in her Foreign Affairs article, “is a direct threat to the United States, because it undermines the very concept of democracy.”

While this vision of planetary struggle is enticing—what leftist doesn’t abhor the oligarchic authoritarianism of Putin, Bolsonaro, Orbán, and their ilk?—it’s also dangerous. Most alarmingly, Warren and Sanders’s dualistic understanding of international relations uncomfortably echoes the Manichaean vision of the Cold War, the same framework they hope to replace.

For decades after World War II, American leaders were possessed by fears that communist triumphs abroad would undermine democracy at home. Communism, so the logic went, was an overwhelming threat not only because of Soviet military might, but because it could diminish American citizens’ confidence in their own democracy. This was the mindset that encouraged generations of US leaders to view the Cold War as a zero-sum struggle; for most American elites, the United States could simply not peacefully coexist with the Soviet Union. As such, foreign policy–makers initiated the largest peacetime military buildup in American history as well as military interventions, political coups, and proxy wars across Africa, Latin America, and, most notoriously, Asia.

In an especially dark irony, the global “fight for democracy” took a toll on egalitarian politics at home, dramatically curtailing efforts to make the United States a more democratic and equal society. The more American elites panicked over communist power abroad, the more they clamped down on domestic dissent, delegitimizing and sometimes imprisoning labor leaders, civil-rights activists, and racial, gender, and sexual minorities.

The binary understanding of international relations proved so powerful that it outlasted the Cold War itself, reemerging after the September 11, 2001, attacks in the War on Terror. “Radical Islam” and the “Axis of Evil” replaced communism as the existential threats du jour. And, like its anti-communist predecessor, post-9/11 paranoia not only sparked foreign disasters in Afghanistan and Iraq but also domestic surveillance and xenophobia.

To be sure, Warren and Sanders have no desire to repeat the brutal mistakes of the Cold War and War on Terror, and both are clearly dedicated to equality and citizen empowerment. But the fact remains that their polarized view of international affairs could subvert the goals of progressive politics. To begin, to combat climate change or global inequality, the United States will need to cooperate with authoritarian states like Russia. Democratic socialists do not choose the world in which we live, and if we categorically reject military intervention—as Sanders has—we must be willing to engage with illiberal and undemocratic governments. Recently, progressives rightfully cheered the end of the Cuban embargo and the nuclear agreement with Iran—two repressive states—because these moves encouraged stability and peace. The same logic must guide our thinking about Russia, Brazil, and North Korea, as kleptocratic as they may be. A progressive mindset that disposes of the notion that US engagement is a prize gifted only to “legitimate” leaders would reaffirm the importance of broad-based diplomacy, which has too often been replaced with military intervention.

More substantially, peace is not served when one envisions American diplomacy as a moral crusade. For too long, American elites have conflated their own agendas with the universal good and have thus been unable and unwilling to appreciate the desires and fears of other nations. To take one prominent example: After the Cold War, US policy-makers refused to take seriously Russian anxieties about NATO’s encroachment into their near abroad, which provoked Russia’s ire and ultimately helped encourage Putin’s annexation of Crimea. Progressive politicians like Warren and Sanders must convince Americans, as well as the foreign-policy establishment, to shed their self-appointed role as moral arbiters and help them understand that countries have their own interests.

Finally, and most crucially, progressive politicians have the urgent task of expanding the American political imagination to include solidarity with foreign peoples. All the major global issues of our day—climate change, nuclear disarmament, inequality—can only be solved through international cooperation. We must therefore reject the notion, held by politicians across the political spectrum, that the United States is necessarily in competition with other nations. (Sanders has made some positive steps in this direction, asserting that climate change “is a crisis that calls out for strong international cooperation.”) To build novel solidarities, progressive leaders like Warren and Sanders must craft a political language that centers the prosperity and well-being of all people, whether or not they are American. Of course, this is an immensely difficult task that will require significant creativity. But it must be accomplished, and casting foreign countries as nefarious enemies is not the way to do so.

None of this is to say that the United States does not have an active role to play in the promotion of progressive values beyond its borders. Its trade agreements should include clauses that protect workers both at home and abroad; its government should withdraw all military and financial support from countries that engage in systematic oppression, from Saudi Arabia to Israel; and its vast resources should be used to alleviate international crises, including the refugee crisis in the Middle East and the incarceration of Uighurs in China. Moreover, progressive civil-society organizations like labor unions and NGOs should work with foreign peoples to help them achieve their goals. But it must also be recognized that a progressive world will never be built if we continue to categorize countries or peoples in Manichaean terms. A wise foreign policy will appreciate the complexities, tensions, and tragedies of international relations and abandon the moralistic pablum that has for too long defined US geopolitics.