In June 1949, the director of the State Department’s Policy Planning Staff, George Kennan, twice brought theologian Reinhold Niebuhr to the group’s meetings as a consultant. Niebuhr returned to speak to the State Department many times during the Truman administration, and was joined in doing so by arch-realist political scientist Hans Morgenthau. According to an attendee at one of the sessions, Niebuhr’s “position was to promote all possible international cooperation and organization, but not to allow utopian visions of world government to interfere with the complicated task of securing the precarious order and justice that were available within the existing system.” That is about as succinct a definition of foreign-policy realism as it is possible to get.

With Kennan, Niebuhr, and Morgenthau all pioneers of this approach to international affairs, those meetings were arguably the high-water mark for realist thinkers in the upper echelons of a Democratic administration. But they were hardly the only times liberals and realists have found profit in allying. And with today’s Republican Party relying almost exclusively on neoconservatives to set its foreign-policy agenda, realists are once again starting to move toward the Democratic Party.

Realism is widely thought to be antithetical to liberalism. This school of thought in American foreign policy emerged in the first place as a reaction against the reckless naiveté of that exemplar of progressivism, Woodrow Wilson. As Morgenthau wrote in his 1948 book Politics Among Nations, a foundational text for realists, Wilson’s pledge to make the world safe for democracy, his promises to support self-determination for all peoples, and his endeavors to make the League of Nations the guarantor of world peace were the very embodiment of utopianism. Certainly the self-righteous Wilson would have found blasphemous the basic postulates of realism: power is the driving force in the world, the international system is impossible to harmonize, stability requires a balance of power, and no country is innocent.

Yet while Wilson unfailingly couched his actions in moralistic language, his decision to involve America in World War I in 1917—rather than much sooner, as Theodore Roosevelt urged—can be seen as a classic realist maneuver. After letting the combatants exhaust themselves for three years while sitting on the sidelines and preserving its power, America intervened to prevent a hostile power—Germany—from rearranging the European balance of power in its favor. In his realist manifesto U.S. Foreign Policy: Shield of the Republic, journalist Walter Lippman, who served in the Wilson administration as an adviser, wrote that the “undeclared” reason for American involvement was that “many Americans saw in 1917 that if Germany won, the United States would have to face a new and aggressively expanding German empire which had made Britain, France, and Russia its vassals, and Japan its ally.” In the Great War, “Wilson’s idealistic vision coexisted with geopolitical realism,” as the journalist-historian Michael Lind put it in his book The American Way of Strategy.

After securing victory for the Allies, however, Wilson jettisoned any semblance of realism and instead embraced a quixotic attempt to remake the world along the lines of universal justice. His Republican successors Harding and Coolidge erred in the opposite direction: they withdrew America from involvement in European affairs, ignoring realist principles by permitting Germany to rearm. As Kennan argued in his classic work American Diplomacy, 1900-1950, “It [is] essential to us, as it was to Britain, that no single continental land power should come to dominate the entire Eurasian land mass.” Such a power would inevitably embark upon an overseas expansion that would jeopardize American security with all the resources of the interior of Europe and Asia, Kennan wrote.

It would take the paradigmatic Democratic president of the 20thcentury to prevent this. Indeed, although FDR is beloved by liberals for leading the fight against fascism, he is equally respected by realists for letting the Soviet Union and Great Britain do most of the fighting against the Nazis and for taming the hostile would-be continental powers of Germany and Japan. “Roosevelt did have certain realist instincts,” says Stephen Walt, a leading international relations theorist at Harvard University’s Kennedy School of Government. But more importantly, says Walt, the world imposed realist logic on Roosevelt. Liberal priorities at the time—spreading freedom, protecting democracy, defeating totalitarianism—overlapped with the realists’ goals of preserving a favorable balance of power.

The beginning of the Truman administration was in many ways the apogee of Democratic foreign-policy realism. With Kennan an influential member of the State Department and Secretary of State George Marshall the most persuasive voice in the president’s ear, Truman reoriented U.S. foreign policy towards containing the Soviet Union. The Marshall Plan that did so much to rebuild Western Europe was, according to Kennan, the quintessential example of his containment theory in practice. The creation of NATO was likewise an essential move for convincing Western Europe of American security commitments. And Marshall nearly single-handedly kept the U.S. out of a potentially cataclysmic war with China, according to the political scientist Robert Jervis.

There is no doubt that the Truman administration also contained significant elements of liberalism and missionary zeal. Expanding the Korean War above the 49th parallel, the Truman Doctrine of aiding any government resisting Communism, a defense build-up beyond what was necessary—these policies lacked the crucial realist element of proportion, as Kennan, Lippman, and others warned at the time.

Yet the Truman administration synthesized a strategy for containing (and eventually defeating) the Soviets without waging war. Despite Truman’s mistakes, even his expanded containment doctrine was more realist-minded than the Republican plan of rollback, a more aggressive, forward-leaning policy than mere containment of the Soviets.

It was only during the Kennedy and Johnson administrations that Democrats fully embraced crusading liberalism. As theorized by Kennan, Morgenthau, and Lippman, containment was only supposed to be applied to Europe, but the Korean conflict convinced policymakers that the Cold War was a global struggle. Kennedy and Johnson pursued this notion to its logical conclusion, ensnaring America in futile, counterproductive adventures in Cuba, Laos, and most disastrously, Vietnam. Nevertheless, “the idea that Democrats are the party of human rights and Republicans are the party of realists is just a caricature,” says Joseph Nye, assistant secretary of defense during the Clinton administration.

Like all caricatures, there is some truth in the drawing. It was left to the Republican Nixon administration to inject realism back into American strategy following the Kennedy-Johnson era. Splitting the Sino-Soviet alliance was a masterstroke, and détente was a wise plan to husband U.S. power in an age of overstretch. Yet Nixon and his right-hand man Kissinger also succeeded in discrediting realism.  Indeed, the term “Kissingerism” was coined to denote a particular brand of ruthlessness in foreign policymaking, so closely did the secretary-of-state-turned-national-security-adviser come to personally embody this approach to the world. In 1976, both Democratic nominee Jimmy Carter and Republican primary contender Ronald Reagan attacked the Nixon-Kissinger-Ford style of foreign policy as amoral, contrasting it with their preferred methods based around human rights and anticommunism respectively. Since then, foreign-policy realism has been shunned by politicians, in public at least, as immoral and contrary to American values.

Ironically, the assumption that Kissinger was, and is, the realist par excellence was flawed from the beginning. While realist-minded in some ways, in other respects Kissinger was anomalous. Nearly all realists opposed both the Vietnam and Iraq Wars—except for Kissinger. Similarly, realists always focused on Western Europe as the leading (usually only) front in the Cold War, but Kissinger and Nixon were obsessed with maintaining strength in the Third World, overthrowing governments and sponsoring coups. They too expanded containment beyond the European theatre, but wrongly claimed to be acting as realists in doing so. “Kissinger’s motives and actions departed significantly from the realist model,” says historian Jeremy Suri, author of Henry Kissinger and the American Century. 

With Kissingerism wrongly conflated with realism, it is no wonder the American public associates the latter with brutality. And even apart from that, there are those who argue that realism can never gain a dependable foothold in this country. They point to the messianic aspects of the American character and argue that liberalism is hard-wired into the country’s DNA. “Getting Americans to support realism is something of an uphill battle,” says Walt. “It often becomes popular in this country only when things get bad.”

But that’s why realism has made something of a comeback in the wake of the Iraq War. That misadventure is a prime example of how seemingly noble aims can lead to disastrous outcomes, both for the United States and for those the U.S. intends to liberate. With its doctrine of preventive war, disdain for allies, and disregard for the probable consequences of failure, the Bush administration was “explicitly anti-realist,” the prominent realist Kenneth Waltz said in 2006. He once voted for Republicans, but “like most of today’s realists, Waltz is now a Democrat—a trend that he views as a reaction to the capture of the Republican Party, from Ronald Reagan onward, by remake-the-world ideologues,” the National Journal reported.

Beginning in 2005 and 2006, the Bush administration embraced a semblance of the realism that had been prevalent in the George H.W. Bush administration. “Bush brought in Robert Gates as Defense Secretary, fired Rumsfeld, and Dick Cheney had much less influence,” says Lind, who notes that there was a sort of palace restoration of his father’s allies. But there are not many Bush I Republicans left to keep filling the palaces of successive GOP administrations.

Realist Republicans are increasingly abandoning their party. “I think the party got carried away with the idea of American exceptionalism,” says Lawrence Korb, an assistant secretary of defense during the Reagan administration. “Reagan resisted the neocons, but under Bush they finally came to power.” A long-time Republican, Korb is now, tellingly, with the Center for American Progress, a leading liberal think tank. “It’s no coincidence that Colin Powell and I both endorsed Obama,” he says. Joining Powell and Korb in doing so were other prominent realists, including Walt, Lawrence Wilkerson, Zbigniew Brzezinski, Robert Pape, and Andrew Bacevich. “I think people from the Nixon administration and the Reagan administration would be comfortable in the Obama administration,” says Korb.

Meanwhile, figures from the first Bush administration, such as Brent Scowcroft and James Baker, are nowhere to be found in the Party of Palin. “The realist community has not been at the forefront of the debate in the party’s evolution,” admits Stefan Halper, who worked in the Nixon, Ford, Reagan, and Bush I administrations. Jack Matlock, ambassador to the Soviet Union during the Reagan administration, says he is no longer a Republican: “Where the GOP leadership has gone has just been appalling.” Matlock, who worked for the first President Bush as well, points to resistance to President Obama’s New START arms-reduction treaty with Russia as a striking example of the Republican Party’s un-realist turn.

Even as recently as the 1990s the Republican Party was hospitable to realism. The party was divided about sending troops to the Balkans and spurned the concept of nation-building. As a presidential nominee in 2000, George W. Bush emphasized humility as his overriding foreign-policy theme. “I’m worried about over-committing our military around the world,” he said during a debate with Al Gore. “I want to be judicious in its use.” The GOP was extremely skeptical of rebuilding failed states. “We don’t need to have the 82nd Airborne escorting kids to kindergarten,” Condoleezza Rice wrote in 2000.

But 9/11 obliterated the realist presence in the GOP. Figures like Scowcroft and Powell were marginalized as Republicans jettisoned their humility and embraced nation-building. “If you look at George W. Bush’s second inaugural address, it sounds like something that could have been written by Woodrow Wilson,” says Nye. So dramatic was the Republican turnaround in foreign policy that by 2008, after serving eight years at President Bush’s side, Rice had reconsidered her comments scoffing at the ineffectiveness of American soldiers taking kids to school: “I still think that’s right, but somebody’s got to do it.”

Now realists and liberals are increasingly lining up on the same side of the political balance sheet on issue after issue: withdrawal from Iraq and Afghanistan, the need for U.S. pressure to force an Israeli-Palestinian peace, diplomacy toward Iran, cutting the defense budget, and protecting civil liberties. “What you’re seeing right now is realists, the left, and some libertarians acting together in opposition to liberal internationalists and the neocons,” says Walt. Michael Lind goes farther: “Obama comes out of the realist wing of the Republican Party,” he says. “I think he is basically a Rockefeller Republican.”

President Obama’s escalation in Afghanistan runs contrary to realist logic, which says that counterinsurgency and nation-building are doomed strategies. His foreign-policy advisers include numerous humanitarian interventionists, who prevailed on him to intervene in Libya last year. But there are at least elements of realism in the Obama administration, which is more than can be said for today’s GOP.  Vice President Biden, for example, has pushed for the president to focus on defeating only Al-Qaeda, not the Taliban, in Afghanistan. “The person Colin Powell called most often when he was secretary of state was Joe Biden,” says Lawrence Wilkerson, Powell’s former chief of staff. Most realists have been disappointed in Obama, but the alternative—a Republican Party that remains in thrall to hawkish ideologues—may be even worse. Realists might have to get used to putting a “D” beside their names. It won’t be the first time they have done so.

Jordan Michael Smith is a contributing writer at Salon.