WASHINGTON—The 2008 American presidential campaign has brought into the open a dramatic soul-searching among conservatives desperate to find a leader and, more importantly, an ideological identity.

A movement that pins its hopes on three different leaders successively in the course of one primary election season is clearly in despair. First, it was the actor and former Sen. Fred Thompson. His candidacy was virtually ordained by conservatives who felt alienated from the Republican field. When Thompson failed to make an impact, those conservatives began to look at Mike Huckabee, the former Southern Baptist minister and former governor of Arkansas, as their standard-bearer. Finally, anxious because of Sen. John McCain’s emergence, they turned to Mitt Romney, the former governor of Massachusetts, whom they had shunned during most of the campaign because of his policy shifts and, less openly, his Mormon faith.

If this quest were not enough to signify a serious problem, the tortuous relationship between the conservative base and McCain should be definitive proof. What are conservatives objecting to? Essentially, that he is not a real conservative. How are McCain’s supporters—including, very recently, President Bush—responding? That he is, well, a real conservative.

Broadly speaking, one can sense that there are three different forms of conservatism in the U.S. today. One type, perhaps reminiscent of the Old Right that opposed Franklin Roosevelt’s New Deal and entry into World War II, believes in individual liberty and an isolationist foreign policy—small government at home and limited intervention abroad. A second group, vaguely descended from Barry Goldwater’s 1964 campaign, believes in small government domestically coupled with a strong foreign policy that will confront ideological enemies abroad. The third group, that of the neocons, pays lip service to small government—but it wants an interventionist judiciary that will uphold certain values, an interventionist government that will make a “compassionate” use of the budget and an interventionist foreign policy that will promote democracy throughout the world.

The lines of demarcation are not always clear-cut, of course. Neocons say they stand for lower taxes too; Goldwater’s political descendents think libertarian Ron Paul is crazy to want to reduce government so much; and McCain sometimes sounds like he belongs in the Old Right on civil liberties and sometimes speaks like a neocon on foreign policy. But, by and large, these are the three competing instincts in the conservative movement. It is not clear how these apparently irreconcilable differences will be resolved and much less who will end up defining and leading American conservatism in the early 21st century.

Here is a start. The last few years should have taught the movement as a whole that some of the goals entertained by the different strands of conservatism are incompatible with each other. You cannot have small government and a foreign policy that seeks to transform the world in your image. You cannot be a “compassionate” government that creates new entitlements and raises every department’s budget—from the Pentagon to agriculture to education—if you really want to reduce spending and the bureaucracy. You cannot use the government to impose certain moral codes and at the same time make individual liberty the bedrock of your political creed.

American conservatives need, first, to define what kind of government they really believe in and then choose the appropriate words to describe that belief. This is a process that conservatives in other countries have also had to go through. Margaret Thatcher’s fall led to open war between “Europhiles” and “Euroskeptics” as well as between radical free-marketers and traditional Tories in the Conservative Party. Many years later, David Cameron has emerged as the leader of a unified party, but it is still unclear whether that unity is partly dictated by the need to get back into government after so many years.

In Spain, the split between the mayor of Madrid and the president of the regional government of Madrid, two political heavyweights in the (conservative) Popular Party, will likely turn into open political warfare to succeed the current conservative candidate for prime minister, Mariano Rajoy, if he loses the general elections in early March. The hatred is personal, but there is also an ideological rift: The mayor favors a greater role for the government against the regional president’s more libertarian approach.

If I were an American conservative, I would not panic. I would relish the opportunity to have that honest, almost therapeutic debate (preferably in opposition) over the next few years and then come back with a clear idea of who we are and where we stand. The entire nation, not just conservatives, would benefit from that cleansing process.