"Why don't we just vote to strike tonight, and we'll decide tomorrow what we're striking for?"

Those were the words of a student protester thoughtfully deliberating at Yale University, as recounted by Roger Kimball in his book on the left, "The Long March." It was a question that captured much of the heedless spirit of the student demonstrations of the 1960s, for which "May 1968" is shorthand.

That spring 40 years ago saw a radical takeover of Columbia University -- eventually duplicated at other elite campuses -- and student protests around the world. In France, the government was rocked to its foundations; in the Eastern Bloc, a crevice was opened up in the Berlin Wall; and here at home, campus life became synonymous with a straitened leftism, and the post-World War II political consensus shattered.

Before we had our long national nightmare (Watergate), we had our long national temper tantrum. In the U.S., student protests were an indulgence of the privileged, a wail by baby boomer kids raised in unprecedented affluence against the authority of their parents. To accuse of "fascism" a generation that bled in the mud of Normandy fighting the Axis took a massive historical ignorance and overweening self-regard; the New Left had both.

Now, we honor the parents of the baby boomers as "the Greatest Generation," but we haven't given up the romance of their kids. We remember the '60s protesters as beatific flower children, aching idealists opposed to the Vietnam War. Airbrushed from the popular imagination is the nihilism, the thrill of the wrecking ball, that animated the vanguard of the New Left.

Means relate to ends. If a movement thrives on the takeover of buildings, non-negotiable demands and threats of violence, it is an unmistakable sign it is coercive and illiberal, no matter how vehemently it invokes "liberation."

The Columbia protests were led by Mark Rudd, whose idea of a bon mot was "Up against the wall, motherf--!" From Columbia's relationship to a Pentagon-affiliated think tank and its plan to build a gym on a city park, Rudd's compatriots concluded that the school was irredeemably militaristic and racist. They occupied university buildings and took a dean hostage before being cleared out (none too gently) by the cops.

Elsewhere, university officials gave in to their tormenters, most notoriously at Cornell a year later. When black students occupied a university building -- ostentatiously arming themselves -- and demanded that disciplinary action against three black students be dropped, the faculty initially stood its ground. When the students escalated their threats, the faculty reversed itself in a signal act of cowardice.

The parents against which the students rebelled -- as represented by the college administrations -- buckled. College presidents who were the finest flowering of post-World War II liberalism gave in to the radicalism, politicizing American higher education and trashing its standards. "The maturation of the student protest movement turned out to be part of the infantilization of the American intelligentsia," Kimball writes.

The freedoms fought for in the student revolt soon curdled into the opposite: free speech became speech codes; sexual liberation became the regime of sexual harassment; civil rights became quotas. Meanwhile, Mark Rudd and a fringe of the New Left spun off into the Weather Underground, which took the destructive spirit of the campus protests to its logical conclusion in a campaign of terrorist bombings. Jonah Goldberg reminds us in his book "Liberal Fascism" that the radical left committed roughly 250 attacks from September 1969 to May 1970.

If the academics gave in, another segment of the parents resisted. They were the Nixon voters, reacting against the disorder and cultural radicalism with which liberalism became identified. Republicans held the White House for 28 of the next 40 years, and the alternative history of the 1960s is the rise of the right. Even now, with Barack Obama dogged by his association with a former member of the Weather Underground, the Democratic Party's challenge is to free itself from the taint of 1968.