The brouhaha over last week’s New Yorker cover illustration of the Obamas as the epitome of terrorist chic extended well beyond the abbreviated news cycle to which we’ve become accustomed.

A New York Times article (which fortuitously appeared the day after the offending New Yorker issue hit newsstands) on the inability or unwillingness of television comedy writers to find anything humorous about Barack Obama was followed 24 hours later by a worried Maureen Dowd ruminating on the Times‘s op-ed page about the cosmic implications of a potentially thin-skinned President Obama, and by the end of the week the debate over the Meaning of It All was in full throttle.

The reaction of most liberals ranged from the usual indignant screeching about racism and jingoism to the equally familiar condescension toward benighted conservatives: “Sure, we intelligent blue-staters get the intended joke, but what about all the rubes in the heartland — the numbskulls who’ve never even heard of, much less read, the New Yorker?”

As the controversy played itself out, it became increasingly obvious that we were witness to a massive case of collective projection. Because if one thing has been evident about American politics over the past several decades, it’s that the left lost its funny bone somewhere between the Tet Offensive and the Nixon reelection landslide — and hasn’t found it since.

While R. Emmett Tyrrell Jr. and P.J. O’Rourke and Andrew Ferguson and Rush Limbaugh and a host of others were giving the lie to the caricature of conservatives as uptight Pecksniffs, the counterculture’s Politics of Rage was evolving into a more sedate, more deadly political correctness, effectively killing off liberal humor.

Once upon a happier time, liberals prided themselves on maintaining a certain detached bemusement. Recognizing – and lampooning – the foibles of even one’s own idols and icons was considered a sign of sophistication, bestowing on its practitioners, deservedly or not, an élan of witty bonhomie.

In Revel With a Cause: Liberal Satire in Postwar America (University of Chicago Press), Stephen Kercher paints a portrait of liberal comedians tweaking liberal and conservative politicians with almost equal verve. Liberal audiences lapped it all up (though not all liberal pols were necessarily amused – Mort Sahl’s jokes at the expense of the Kennedys led to his being blackballed, with the owner of a Los Angeles nightclub telling Sahl he’d been warned “the White House would be offended if I hired you and I’d be audited on my income tax” and another club owner stating that his refusal to cut Sahl loose led to an IRS audit and his being put out of business).

The 1960’s in particular were a golden age of liberal humor, but Lenny Bruce was as likely to excoriate liberal hypocrisy as he was to score conventional morality; the writers of the mid-‘60s political satire television program “That Was the Week That Was” hardly spared their fellow liberals from ridicule; and even as politics took on a more apocalyptical tone in the late ‘60s, shows like “Laugh-In” and “The Smothers Brothers Comedy Hour,” while decidedly liberal in tone, were equal-opportunity offenders.

To better appreciate how things have changed, consider the following bit of commentary delivered by the legendary radio humorist Jean Shepherd, a self-described liberal, during the 1960 presidential campaign, and ask yourself who would be a better bet to jest in such terms today, a liberal or a conservative:

If you have any politically minded type friends, you know — the indignant Liberal or the shell-bound Reactionary — they both talk exactly the same, because underneath, underneath that simple, homespun exterior, there’ll always beat the heart of a true Neanderthal. Doesn’t make any difference what direction it takes, you know?…If you ever really were going to chase the money changers out of the temple, daddy, there would be no temple anymore.