By 1968, Walter Lippmann, the dean of liberal columnists, had concluded that liberalism had reached the end of its tether.
In that liberal epoch, the 1960s, the Democratic Party had marched us into an endless war that was tearing America apart.
Lyndon Johnson's Great Society had produced four "long, hot summers" of racial riots and a national crime rate that had doubled in a decade. The young were alienated, the campuses aflame.
Lippmann endorsed Richard Nixon.
For forty years, no unabashed liberal would be elected president.
Jimmy Carter won one term by presenting himself as a born-again Christian from Georgia, a peanut farmer, Naval Academy graduate and nuclear engineer. Bill Clinton ran as a centrist.
So toxic had the term "liberal" become that liberals dropped it and had themselves rebaptized as "progressives."
Barack Obama, however, ran unapologetically as a man of the left. An opponent of the Iraq war, he had compiled a voting record to the left of Bernie Sanders, the socialist senator from Vermont.
And Obama proudly placed his signature achievement, Obamacare, right alongside, and in the tradition of, liberal giants FDR and LBJ.
This is the new progressivism of the 21st century, Obama was saying, and I the transformational figure who will usher in the post-Reagan era. Where Clinton failed, I will succeed.
But now that Obamacare is coming to be perceived as a political catastrophe, not only does it threaten Obama's place in history, it could invalidate, indeed, eviscerate the defining idea of the Democratic Party itself.
For Democrats are the Party of Government. They believe that government is more nobly motivated than a private sector that runs on self-interest and the profit motive, and that government can achieve goals private enterprise could never accomplish.
To liberals, government is us, the personification of the nation.
Social Security, Medicare, Medicare and the Civil Rights Act of 1964 are monuments to this belief. So, too, are the world wars fought and won under liberal presidents Woodrow Wilson and FDR.
It was 1968, the Tet Offensive, the assassinations, the urban riots, the campus anarchy, the smash-up of the Democratic Party in the streets of Chicago that caused the national recoil from liberalism that lasted for forty years.
Now consider what the rollout of Obamacare is doing, not only to this president and his administration, but also to the idea that government has the solution to America's problems.