Pat Buchanan may have come in a distant fifth in the Iowa straw poll, lost the mantle of leader of the religious right to Gary Bauer and generally crashed and burned his quest for the Republican presidential nomination. But he remains the most interesting candidate in the presidential field.

This is not just because he, so liked by his fellow pundits, can get away with such outrageousness as threatening the Chinese with having sold their "last pair of chopsticks in any mall in the United States of America." Or demanding that the Ivy League -- now about 50 percent Jewish and Asian -- "look more like America" by reserving 75 percent of its slots for "non-Jewish whites."

That is what makes Buchanan so appalling, and entertaining. (In politics, as in show biz, allied qualities.) But he is interesting as more than an entertainer. He is interesting because he is the supreme articulator of what since Pearl Harbor has been an exotic political tendency in America: reactionary conservatism.

Of course, Buchanan would reject the label. He claims to be the one true heir to Ronald Reagan. But on practically every major point of ideology, he diametrically contradicts his former chief. Reagan stood for the classical conservatism of free trade abroad, free enterprise at home, government deregulation and an expansive view of America's role in the world.

Buchanan, on the other hand, has an 18th century mercantilist's contempt for free trade, bitterly opposing NAFTA and the World Trade Organization. He advocates government intervention in the economy to save American jobs, particularly for failing manufacturers and small farmers.

His world view is narrow and inward: His city on a hill is an anti-trade, anti-immigrant Fortress America. He would withdraw projected American power from Europe, the Middle East and practically everywhere else in the world. He still can work up a Reaganite lather heaping scorn on the Beijing Chinese, a nostalgic reprise of the old anticommunism. But that is about it. Except for the soft spot he reserves for Croats, he seems to have no use for foreigners at all.

Why is Buchanan interesting? Because his split with Reaganism exposes the twin character of conservatism. There is the forward-looking conservatism whose major project is the advancement of liberty (what a century ago was known as classical liberalism). This generally describes Reaganism, with the exception of its occasional nods toward -- though tellingly few acts of -- social regulation (censorship, banning abortion and the like).

Buchanan represents that other type of conservatism, the literal attempt to conserve the past, freeze it and recreate it. Which invariably involves economic and social regulation by government -- such as tariffs to protect a dying textile industry -- to undo the changes wrought by modernism.

Ironically, Buchanan's reactionary conservatism shares much in principle with modern liberalism -- "reactionary liberalism" as Kevin Phillips once dubbed it -- which also seeks to use the power of the state to restrict both markets and private action, though in the name not of morality but of hygiene. (Liberals want to save you not from abortion and pornography but from tobacco and SUVs).

In Buchanan's telling, he and his fellow Goldwaterites seized the Republican Party for conservatism in 1964. But what he does not seem to recognize is that Reagan effectively redefined that conservatism in 1980 with an expansive vision that dominates the Republican Party to this day. In such a party, Buchanan really has no home. His problem is not Iowa; it's his ideology.

I disagree with practically everything he espouses. Nonetheless, his coherent worldview makes him a political figure far more substantial than his poll-driven opposition.

If he stays in the Republican primaries he will simply disappear. His only hope is a third party and a seat at the table in next year's presidential debates. (The Reform Party is enticing, because under our insane campaign laws it will be given $12.6 million in taxpayer money; unfortunately for Pat, it is distinctly liberal on social policy.) Nonetheless, a third-party run is his only chance to avoid becoming another Harold Stassen, forever futilely seeking the nomination of a party that two decades ago embraced a far different conservatism.

Buchanan's biggest problem is that these are good times, and good times are bad for parties of reaction and resentment. But good times don't last forever. If Pat can mount a third-party run and do respectably well even in the sunny, booming economy of today, he may go from sideshow barker to founder of something as potentially significant as it is scary.