Once we examine not only their policies, but the ideas that animate these policies, it becomes evident that the two candidates embrace radically different understandings of the United States’ role in the world, each of which implies a distinct future for the nation’s foreign policy.

In fact, it is true that, as Kilgore states, Sanders and Warren in some respects share “very similar policy agendas.” But such similarities obscure the profound differences in their approach and understanding of modern politics. This is nowhere truer than in the realm of foreign policy, the issue area over which American presidents are able to exert the greatest influence.

Despite their avowed and admitted differences, some pundits have attempted to paper over the distinctions between the two candidates. As New York ’s Ed Kilgore aptly summarizes , there is a “prevailing tendency [in the media] to treat Elizabeth Warren and Bernie Sanders as fellow progressives jockeying for position in the left ‘lane’” of the Democratic party.

The most important battle the American left has waged in generations is presently being fought on the Democratic primary stage. On one side stands Bernie Sanders, the first avowed socialist to come close to the presidency since Eugene V. Debs received 6 percent of the vote in the 1912 election. On the other side stands Elizabeth Warren, a liberal Harvard professor who made her career as an expert in bankruptcy law. The victor in this struggle has the potential to set the course for the next decade, or more, of progressive politics.

Beyond the Nation

At first glance, Sanders’s and Warren’s foreign policies appear quite similar. Both want to reduce the defense budget, remove troops from Afghanistan and increase development aid to the country, end “endless wars,” move beyond the “war on terror,” restrict the authority of the imperial presidency, increase labor’s power vis-à-vis multinational corporations, transform the US-Saudi relationship, limit the policy influence of defense contractors, punish Russia for electoral interference, reaffirm the transatlantic alliance, strengthen the State Department and US diplomacy generally, and embrace a multilateral approach to world affairs.

But when one takes a step back and interrogates the assumptions that undergird Warren’s and Sanders’s support for these policies, the differences between the candidates come into stark relief. Most troubling for a socialist left devoted to international solidarity is Warren’s nationalism — what one might call, with only a slight degree of irony, her “America First” approach to world affairs.

Throughout her speeches and writings on foreign policy, Warren makes it abundantly clear that she wants to “protect American interests first and foremost.” Similar to all post–Cold War US presidents, she is dedicated to preserving US “global leadership,” a euphemism for empire that became popular in the Vietnam War’s wake. Her “A Foreign Policy for All” is, in essence, a foreign policy for all Americans that takes the nation-state as the natural subject of politics and history.

Sanders, in contrast, adopts an explicitly global understanding of the United States’ world role. For him, the purpose of US foreign policy is not to reaffirm US “leadership,” but to create “a global community in which people have the decent jobs, food, clean water, education, health care and housing they need.” In a radical departure from the nationalist rhetoric of Warren — and American politics generally — Sanders emphasizes his desire “to reconceptualize a global order based on human solidarity, an order that recognizes that every person on this planet shares a common humanity.” Where Warren’s campaign says she will “stand up for the American economy, fight to protect American workers, and defend American values,” Sanders’s campaign states that “he will change the terms of the global economy to lift up workers everywhere, reversing the race to the bottom” that, he argues, compels “American workers to compete with desperate workers in Vietnam who make less than a dollar an hour and migrant computer workers in Malaysia who are working as modern-day slaves.” As this suggests, Sanders, unlike Warren, is a globalist in the best sense of the term.

Sanders’s empathy for non-Americans emerges clearly when one compares his understanding of the history of US foreign policy to Warren’s. Unsurprisingly, Warren, like many members of the liberal establishment, insists that one of the United States’ great achievements after World War II was its creation of a “liberal international order” “based on democracy, human rights, and improving economic standards of living for everyone.” Though she admits that this order “wasn’t perfect,” she nonetheless avers that, on balance, “our foreign policy benefited a lot of people around the world.” It’s for this reason that she can, with a straight face, express her commitment to US “leadership.”

Sanders adopts a completely different — and, according to most historians, more accurate — understanding of US history. Unlike Warren, or for that matter any other Democratic candidate, he appreciates that for most people the US-led world order “failed to deliver on many of its promises.” In various speeches, Sanders has highlighted the manifold crimes the United States committed throughout the so-called “American Century”: overthrowing Iran’s Mohammad Mosaddegh in 1953, contributing to the ouster of Chile’s Salvador Allende in 1973, and “support[ing] murderous regimes in El Salvador and Guatemala,” to name just a few. Because Sanders actually acknowledges the villainous behavior of Americans during the era of US “leadership,” he is willing to forthrightly place limits on US power. In a statement he gave on Venezuela, for instance, he declares that “the United States has a long history of inappropriately intervening in Latin American countries” and categorically asserts that “we must not go down that road again.” As yet, Warren has offered no similar remarks.

Alone among the major candidates, Sanders’s foreign policy centers the experiences of the Global South. One sees this when comparing how he and Warren answered a question from the Council on Foreign Relations concerning the future of US-African relations. For her part, Warren maintains that under her administration she would support a litany of good governance reforms that combat “wealth concentration, kleptocracy, and corruption” and encourage “transparent governance and more equitable, inclusive growth” throughout the African continent. Against this implicitly hierarchical approach, in which the United States helps save Africans from themselves, Sanders asserts that “America must create room for Africa to play a greater role in setting the global agenda or else we will repeat the colonialist/imperialist history of the 19th and 20th centur[ies] that suppressed African opinions and impoverished Africa.” Put another way, Sanders desires to establish a world in which the countries of Africa become the subjects, instead of the objects, of international politics — a profound reversal of centuries of colonial and neocolonial oppression.

Indeed, Sanders’s sensitivity to the history of colonialism leads him to make empowering Puerto Rico, one of the five inhabited territories undemocratically controlled by the United States, a platform of his campaign. In fact, he’s appointed Carmen Yulín Cruz, the mayor of San Juan, one of his campaign co-chairs.

It is from this perspective that Sanders rejects the nationalist politics of Warren and advocates organizing a “global progressive movement that speaks to the needs of working people” in all countries. “The goal,” he avows in no uncertain terms, “is not for the United States to dominate the world” but to foster “global engagement based on partnership, rather than dominance.” This is a radical departure from the primacist and nationalist assumptions that have guided US foreign policy since World War II and that continue to permeate Warren’s thinking.

The differences between Warren’s nationalist and Sanders’s global frameworks engender differences in how each understands future geopolitical challenges. For Warren, the major problems the United States will confront in the coming years are “a long-term struggle [with China] for power in Asia, a revanchist Russia that threatens Europe, and looming unrest in the Western Hemisphere” exemplified by “a collapsing state in Venezuela that threatens to disrupt its neighbors.” According to her, US elites need to continue to center the nation in their visions of international relations. Furthermore, by presenting Asia, Eastern Europe, and the entire Western Hemisphere as standing within the United States’ sphere of influence, Warren subtly reaffirms the importance of a distinctly nationalist US hegemony.

Sanders, by comparison, has argued that climate change and global inequality — two worldwide phenomena — are the United States’ primary future problems. As such, he underlines the necessity of collaborating with China, Russia, India, and other countries to address these challenges of the global commons. In fact, Sanders implies a post-nationalist understanding of international relations when he notes that the era in which the United States confronted “a superpower adversary with a huge standing army, with an arsenal of nuclear weapons, with allies around the world, and with expansionist aims” is long over; now, the chief threats to security cross borders. And when he does admit that the United States, due to its enormous power, has a leading role to play in solving these problems, he emphasizes that US leadership must be dedicated to facilitating international cooperation. It is not for nothing that Sanders has cited the Marshall Plan and the creation of the United Nations as the United States’ most significant post-World War II achievements.

Indeed, Sanders affirms that only a global movement will be able to solve the challenges the United States, and the world, confront. This movement is decidedly not nationalist but is instead premised on “unit[ing] people all over the world” who embrace “a vision of shared prosperity, security and dignity for all people.” As this suggests, Sanders has adopted a capacious vision of geopolitics that sees not only government-to-government, but people-to-people, diplomacy as crucial.