The Death of Conservatism. Sam Tanenhaus. Random. 144 pages. $17.

Despite its title, Sam Tanenhaus' new book is not another premature eulogy for a political movement. In fact, it's a sound diagnosis of a disfiguring ideological disorder that has turned contemporary conservatism into a monstrously unrecognizable shell of its classical self. But the afflicted are too far gone to pay heed. In the next few weeks, Tanenhaus can expect to be dismissed and denounced as a useful idiot of the left. This will only lend further credence to his argument that the Republican Party has been overrun by reality-denying radicals who would rather nurse perceived grievances than engage the changing cultural zeitgeist.

Tanenhaus is exceptionally well-versed in his subject. Before assuming the editorship of The New York Times Book Review, he penned a balanced account of the life of Whittaker Chambers, the ex-Communist spy who informed on Alger Hiss. Chambers was revered and befriended by William F. Buckley Jr., whose authorized biography Tanenhaus has been working on for several years.

Buckley fought to make the right acceptable to the American mainstream. Now it's being pushed back to the margins. Today's so-called conservatives claim to have inherited the mantle of the 18th century statesman and philosopher Edmund Burke, but Burke viewed government favorably and embraced the notion of compromise. He believed in preserving established institutions, even when they were not to his liking. This was the basis for his memorable attack on the French Revolution. Tanenhaus detects a Jacobin strain in the rhetoric of ``noisemakers and pyrotechnicians'' such as Rush Limbaugh and Newt Gingrich. Next time you listen to Limbaugh, picture Marat scribbling in his tub. If he had his way, no constitutional check would be honored if it jeopardized the implementation of his agenda. Power over precedent, half-baked principle in lieu of policy -- the raison d'etre of the patriotic traitor. ``They not only abandoned Burke,'' Tanenhaus writes, ``they became inverse Marxists, placing loyalty to the movement -- the Reagan Revolution -- above their civil responsibilities.''

Tanenhaus sketches a fine overview of the movement's implosion. The pearly prose is a delight to read, and the observations brim with insight. For example, a comparison with the New Left of the 1960s is invoked. Just as the behavioral and rhetorical excesses of the counterculture disgusted the normative majority, the New Right has alienated voters with its expedient embrace of anti-intellectual populism, the fundamentalist social agenda and a preemptive-strike policy.

Still, Tanenhaus believes the GOP can rise again if it abandons sandbox tactics and finds common cause with Barack Obama, who ``seems more steeped in the Burkean principles of `conservatism' and 'correction' than any significant thinker or political figure on the right today.'' Time will tell if a kumbaya moment comes to pass.

Ariel Gonzalez teaches English at Miami Dade College.