WASHINGTON—A rebellion is beginning to take place among American conservatives, many of them influential commentators who are denouncing the takeover of the Republican Party by a mixture of anti-intellectual populists and political extremists.

Novelist Christopher Buckley, the son of the founder of modern American conservatism, has endorsed Barack Obama for president. Columnists Kathleen Parker and Peggy Noonan have questioned John McCain’s judgment in picking Sarah Palin as his running mate. Another columnist, David Brooks, has offered a jeremiad against the Republican Party’s anti-intellectual bent.

More poignantly, they all decry what they perceive as a betrayal of conservative principles. Buckley put it succinctly when he wrote that George Bush’s government has brought America “a doubled national debt, ruinous expansion of entitlement programs, bridges to nowhere, poster boy Jack Abramoff and an ill-premised, ill-waged war conducted by politicians of breathtaking arrogance.” Brooks thinks the problem goes beyond the Bush years, stating that “modern conservatism began as a movement of dissident intellectuals” against the liberal domination of the academic world, but “what had been a disdain for liberal intellectuals slipped into a disdain for the educated class as a whole.” Parker is even more forceful: “The well-fed right now cultivates ignorance as a political strategy. ... Years of pandering to the extreme wing ... have created a party no longer attentive to its principles.”

We don’t know if these symptoms of dissent will develop into a full-blown rebellion against the Republican establishment. Much will depend on the result of the presidential election. If McCain and Palin lose, the chances of an insurgency taking root within the party itself are significant.

The Republican Party has indeed deviated from conservatism as it is understood by those who consider Edmund Burke the founder of the conservative idea, William F. Buckley the intellectual midwife of modern-day American conservatism, and Barry Goldwater the flint that sparked a vast political movement in favor of small government in the United States.

This deviation expresses itself in different ways. First, in the confusion between Jeffersonian populism—a salutary mistrust of economic power allied to political power—and class-based populism, which is what Republican leaders promote when they scorn America’s coastal and big-city culture. Second, in the contradiction between a low-tax, low-spend policy and an interventionist foreign policy that, by definition, is costly—as every empire in the history of mankind eventually and painfully found out. Last, in modern-day Puritanism, which started, perhaps understandably, as a reaction against the cultural excesses of the 1960s but ended up turning into what H.L. Mencken described decades earlier as “grounded upon the inferior man’s hatred of the man who is having a better time.”

These fundamental deviations from conservatism crystallized in the Bush administration. The result was the biggest growth in government since the presidency of Lyndon Johnson, a loss of international prestige and, in purely political terms, the alienation of millions of people who could have been attracted to the Republican Party had its libertarian roots been preserved in dealing with social issues. Thus, the party that styles itself the champion of individual liberty has come to be seen by many in the United States and around the world as a special-interest group driven by factions and devoid of principle.

That many conservatives have finally decided to speak out is encouraging. That they are being vilified is even more encouraging—it means that they may just have a point. After the elections, conservatives will have to do some serious soul-searching and ask themselves a few simple questions: How was it that they let their movement and their party be hijacked by people who were hellbent on disfiguring the face of American conservatism? How was it that the self-styled party of individual liberty became, in the eyes of many, the party of big government, intolerance and jingoism?

The recent spats among the various strands of American conservatism are the harbinger of a transcendent fight for the soul of the movement. We don’t yet know who the leaders will be and much less who will emerge victorious. The search for a renewed Republican Party could, as in 1964 and 1980, produce a return to its roots. But this will not be a pretty picture. If the “root” conservatives are going to displace the faction that now controls the movement, they will need to displace some very unpleasant people.