The ghost of Howard Dean haunts the pundit class. As soon as a candidate of either party spikes up in the polls, he is compared with Dean, who had a spectacular boomlet in the second half of 2003 only to deflate as soon as people began to vote in early 2004.

After many false prophecies, Dean circa 2008 has finally arrived. He is former Arkansas Gov. Mike Huckabee. Not because he will inevitably blow himself up in Iowa. But because, like Dean, his nomination would represent an act of suicide by his party.

Like Dean, Huckabee is an under-vetted former governor who is manifestly unprepared to be president of the United States. Like Dean, he is rising toward the top of polls in a crowded field based on his appeal to a particular niche of his party. As with Dean, his vulnerabilities in a general election are so screamingly obvious that it's hard to believe that primary voters, once they focus seriously on their choice, will nominate him.

The GOP's social conservatism inarguably has been an enormous benefit to the party throughout the past 30 years, winning over conservative Democrats and lower-income voters who otherwise might not find the Republican limited-government message appealing. That said, nominating a Southern Baptist pastor running on his religiosity would be rather overdoing it. Social conservatism has to be part of the Republican message, but it can't be the message in its entirety.

Someone needs to tell Huckabee. His first TV ads in Iowa touted him as a "Christian leader," and his target audience of evangelicals has responded. But according to a Pew poll released in early December, only 1 in 7 nonevangelical Republicans support him in Iowa and 1 in 20 nonevangelicals in New Hampshire and South Carolina.

Huckabee has declared that he doesn't believe in evolution. Even if there are many people in America who agree with him, his position would play into the image of Republicans as the anti-science party. This would tend to push away independents and upper-income Republicans. In short, Huckabee would take a strength of the GOP and, through overplaying it, make it a weakness.

He'd do the same on taxes. In general, the public tends to support Democratic proposals for bigger government, which Republicans counter by saying that the proposals will require higher taxes. Huckabee will be equipped poorly to make this traditional Republican comeback, given his tax-raising history in Arkansas. Huckabee tries to compensate with a sales-tax scheme that allows him to say he supports eliminating the IRS, but is so wildly implausible that it would be a liability in a general election.

Then, there's national security, the Republican trump card during the Cold War and after 9/11. Huckabee not only has zero national-security credentials, he basically has no foreign-policy advisers either, as a New York Times Magazine piece this Sunday makes clear. In a speech at the Center for Strategic and International Studies in September, Huckabee struck notes seemingly borrowed from Barack Obama, hitting the Bush administration for its "bunker mentality" and strongly supporting direct talks with Iran. A foreign-policy debate with a Democratic nominee would be a competition over who can promise to be nicer to foreign countries.

None of this is a winning formula. Huckabee has been running his campaign out of his back pocket, and has done it extremely well. There's a reason, though, that serious candidates surround themselves with policy experts. It's necessary to running a campaign based on more than sound bites. Wherever you scratch Huckabee on policy, he seems an inch deep. Do Republicans really want to enter what is already a tough political year with a candidate apparently allergic to preparation, and who has shown no predilection for organizing or fundraising, when he can do cable TV appearances instead?

Democrats have to be looking at Huckabee the way Republicans once regarded Dean -- as a shiny Christmas present that is too good to be true.