For Senator Rand Paul, winning the Republican presidential nomination will involve a delicate balancing act of keeping faith with his libertarian roots while also appealing to the broader conservative base of the party. On issues like the war on drugs and government surveillance, Paul has articulated strongly anti-statist positions that are rarely heard from either party. Yet to be a plausible Republican presidential candidate, Paul, to the disappointment of many of his more orthodox libertarian followers, is increasingly sounding like a typical conservative, especially on foreign policy.

Paul’s conundrum shouldn’t surprise us: Libertarians have always been an uneasy fit within the broader Republican coalition. Libertarians claim to have roots in classical liberalism of the early modern era, but only emerged as a salient and self-conscious political movement in the 1930s, as a reaction to the expansion of the welfare state initiated by Franklin Roosevelt’s New Deal. That didn’t make libertarians comfortable Republicans, though. As purist counter-revolutionaries who wanted to roll back FDR’s achievements, libertarians all too often found Republicans to be cowardly and unreliable allies. In 1940, Ayn Rand, later famous for her didactic pro-capitalist potboilers, campaigned for Republican candidate Wendell Willkie. The experience was disillusioning for Rand, who concluded that GOP timidity itself was the main hurdle to fighting socialism. “Nobody can defeat us now—except the Republicans!” Rand wrote to a friend in 1943.

Over the next 70 years, Rand’s disenchantment with the Republicans would be sounded with dismaying regularity by prominent libertarians, who would often prefer to make common cause with eccentric fringe political formations—including left-wingers—rather than the party of Eisenhower, Nixon, and the Bushes.

The late Murray Rothbard, a towering intellectual and political activist in libertarian circles, was a striking example. During the 1940s, he belonged to New York’s Young Republican Club, but during the Cold War he concluded that the GOP’s militarism was a betrayal of the traditional anti-war and isolationist principles of the Old Right. During the 1950s, Rothbard preferred Democrat Adlai Stevenson to Eisenhower, and while some other libertarians like Milton Friedman jumped on the Goldwater bandwagon in the early 1960s, Rothbard still distrusted the Republicans. “Goldwater and the Conservative Movement are not only not libertarian, but the preeminent enemies of liberty in our time,” Rothbard wrote in 1964 in a letter to a small libertarian magazine called the Innovator. “For the Goldwaterites are, first, aggressive and ardent champions of American imperialism and intervention in political affairs all over the globe; and, second and most important, are eager advocates of nuclear war against the Soviet Union.” During the heady days of the late 1960s, when he dreamed of a new politics cutting across the traditional left-right spectrum, Rothbard even forged an alliance with the Maoist Progressive Labor Party, preferring them to Nixon’s Republicans.

Although Rothbard had a propensity for extremist gestures, he shouldn’t be dismissed as a fringe figure, at least not among libertarians. His application of Austrian economic theory to America, formulating a critique of the Federal Reserve as a central source of bad policy, was widely influential, not least on Rand Paul’s father, Ron Paul. Moreover, Rothbard’s allergic reaction to the Republican Party was widely shared within the libertarian movement, culminating in 1971 with the formation of the Libertarian Party (LP).