It is and has been, a long marriage made in worldly (and too often the Catholic world) heaven and this article from City Journal captures the recent history.

An excerpt.

Shortly after taking power in 1959, Cuban dictator Fidel Castro took up Vladimir Lenin’s old strategy of gaining the support of “progressive” intellectuals in Europe and the United States. Lenin called them “useful idiots.” French writers Jean-Paul Sartre and Simone de Beauvoir became Castro’s first marks.

The couple embodied the intelligentsia in its purity and perfection: they led a bourgeois life in Paris, they posed as revolutionaries, and they had a woeful record of predicting the future. During World War II, they never publicly denounced the Nazis and continued to publish undisturbed in France. After the war, they supported Stalin, then the Communists of North Vietnam, then China’s Mao Tse Tung. In 1960, they accepted Castro’s invitation to Havana, where they were received like royalty. They responded by publishing celebrations of the Cuban revolution. They never seemed to grasp that the Castro regime was a typical Latin American caudillist dictatorship, wrapped up in Marxist language to secure Soviet protection.

There is no question that Sartre was useful for Castro, but was he really an idiot? Is it possible that the great writer saw and understood nothing on his trips to Havana, Moscow, and Beijing? It is more probable that he saw and understood everything, but judged it advantageous to claim that he didn’t. In the 1950s, completely informed of the existence of the Soviet Gulag and urged by Russian dissidents to denounce the prison camps, Sartre serenely kept his mouth shut, in order, as he said, “not to drive Billancourt to despair.” Billancourt was at that time the Paris suburb considered a “working-class fortress,” where 30,000 workers manufactured Renault automobiles. Did Sartre really believe in a universal proletarian revolution carried out by Stalin, Castro, and Mao? This proclaimed faith in a collective liberation doesn’t cohere with the profoundly individualist philosophy of his writings.

I knew Sartre a little personally in the 1970s. I, too, made the pilgrimage to Havana, Moscow, and Beijing (though I went in order to denounce the dictators). It always seemed to me that Sartre placed himself above the revolution—and above humanity in general. He was a Machiavellian: he believed in one morality for the elites and another for the people. Castro understood that Sartre was moved by vanity. The dictator showered the public intellectual with honors and bestowed upon him hours of personal audience. Sartre was rich; he didn’t need to be bought, but his moral corruption was boundless.

Beyond Sartre’s case, which, to be sure, provides an archetype of intellectual idiocy, most of those who worshiped dictators have obtained the rewards they sought—recognition that they couldn’t find in their own countries. After Sartre came a stream of intellectuals from East and West. Susan Sontag led the way for the United States. Intellectuals of the Left have always lusted after power. For this reason, they detest materialism, capitalism, and the United States. Democracy does not accord power to philosophers.