Libertarians and other advocates of a noninterventionist foreign policy—or its close cousin, a policy of realism and restraint —have grappled with how to respond to the candidacy of Donald Trump. Some of Trump’s policy positions are refreshing and sensible. His hostility to wars for regime change and nation building are a gratifying contrast to the enthusiasm for such ventures that both neoconservative Republicans and humanitarian interventionist Democrats have exhibited in recent decades. Trump’s insistence that America’s longstanding allies in both Europe and East Asia do far more for their own defense also has at least the potential to significantly reduce the republic’s excessive and obsolete security burdens. Finally, his desire to avoid confrontational relationships with major powers such as Russia and China is a rare voice of prudence among America’s political elite, and it has understandable appeal to noninterventionists.

But there are other Trump positions that are deeply disturbing, if not outright offensive to the kind of noninterventionists (or “cosmopolitan realists”) who have filled the ranks of Cato’s foreign policy program. Trump’s hostility to free trade is both disappointing and myopic. But his stance on immigration is even worse. His proposal to build a wall along the border with Mexico to keep out undocumented Hispanic migrants is not only impractical, it conveys a message of hostility to such populations. Trump’s stance on Muslim immigration, especially his call for a “temporary” ban, conveys such hostility with even greater clarity.

His support for trade protectionism, combined with adamant opposition to liberal (or even reasonably humane) immigration policies, and indeed his overall xenophobic rhetoric understandably alienate more cosmopolitan noninterventionists. What they may find difficult to admit, though, is that Trump’s type of insular, intolerant nationalism has a long history within the noninterventionist camp.

Some of the same political figures who staunchly opposed U.S. involvement in foreign wars and participation in “entangling alliances” during the first half of the twentieth century also supported extremely restrictive immigration quotas in the 1920s and subsequent decades. Even Sen. Robert A. Taft (R‑OH) the leader of the dwindling post-World War II noninterventionist contingent in Congress had a mixed record. He correctly warned that some of the new security partners Washington was acquiring would both besmirch American values and drag the republic into avoidable conflicts. He even dared to oppose NATO membership for the United States, warning presciently that the European nations would come to depend far too much and far too long on America for their security.

But Taft was not especially good on trade and immigration issues. And other prominent noninterventionists of that same period, such as Sen. William Jenner (R‑IN), Sen. Kenneth Wherry (R‑NE), and Sen. .John Bricker (R‑OH) were even more stridently insular. Bricker is best known for sponsoring a constitutional amendment insisting that no treaty could supersede or override any provision of the U.S. Constitution. There was nothing wrong with that position per se, but Bricker and his allies used the campaign to whip up public hostility toward the United Nations and America’s other international obligations—even entirely nonmilitary obligations.

Moreover, one ought to keep in mind that all of the men mentioned above (even the usually sensible Taft) were strong supporters of Senator Joseph McCarthy’s unconstrained and often irresponsible hunt for domestic communists in the 1950s—a witch hunt that shattered careers and lives. They were willing to sacrifice important civil liberties in the name of national security. In other words, enthusiasm for authoritarian methods has been part of the makeup of some noninterventionists for a long time. Donald Trump did not invent that behavior.

Such an admission is very difficult for noninterventionists who have worked hard to chart a different, far more open and generous course for that doctrine. Cosmopolitan realism seeks to promote maximum, peaceful interaction among diverse populations around the world. Therefore, it is hardly surprising that such noninterventionists favor free trade and liberal immigration policies, even as they vehemently oppose the use of force except in the direct defense of the independence, security, and liberty of the American people. The question remains, though, how such committed cosmopolitan realists should respond to potential ideological allies who share some, but definitely not all, of those values. Trump’s candidacy has now brought those concerns to the forefront.