At a conference of conservatives, young Democrats handed out a three-page missive ridiculing three leading Republican presidential candidates as The Three Stooges.

In the context of modern political discourse, the attacks on Sen. John McCain, R-Ariz., ex-Gov. Mitt Romney of Massachusetts and former New York Mayor Rudolph Giuliani were rather tame. But a couple of paragraphs on Giuliani’s marital problems – he’s been married three times and had a messy public divorce while mayor – were notable for two reasons.

First, the mention seems curious coming from a Democratic Party that argued throughout Bill Clinton’s 1998-1999 impeachment and acquittal that Republicans had overreached in the Monica Lewinsky scandal, that it was merely about sex between consenting adults (and the product of a “vast right-wing conspiracy” in then-first lady Hillary Rodham Clinton’s words).

Second, it signals that despite admonitions from Hillary Clinton’s supporters that the impeachment should be irrelevant to her presidential candidacy, Democrats expect it to come up if Clinton gets her party’s nomination. This attack on Giuliani was likely not the last you will hear from Democrats about messy marriages.

The attack signifies a particular trait of the evolving presidential primary fields in both parties. Rarely have so many candidates had so many open flaws to overcome on their way to the nomination. One might even say the nominations and the presidency will go to the man or woman best able to cover their flaws.

For Clinton, it is the image she is a chameleon, trying to be too much to too many. Little stories have illustrated this claim in her public life. Her claim to love both the Cubs and Yankees – parallel universes to true baseball fans – come to mind.

Rival Barack Obama, the first-term senator from Illinois, confronts a lack of experience. Ex-North Carolina Sen. John Edwards is trying to confront the image that he is glib but not deep and may himself be too inexperienced even with a substantive health care reform plan.

On the GOP side, Giuliani’s marital problems, and his support of abortion and gay rights, is supposed to eventually sour social conservatives. Romney, a Mormon, has become a recent conservative convert on abortion and gay rights, but there are doubts among evangelicals about his religion and among cultural conservatives about his sincerity.

And McCain has lost the maverick luster that propelled him in the 2000 Republican primaries by aligning himself with President Bush on the unpopular Iraq war and making peace with religious right leaders he attacked as intolerant seven years ago.

The media focus will come off these six at some point, probably in late summer about the time of an August straw ballot in Iowa. And the surviving “second tier” candidates – described that way because they may be unable to raise the $100 million or more that is supposed to constitute a serious candidate – will have an opportunity to make their case.

That process might hold a surprise or two. Sen. Sam Brownback, R-Kan., has problems with conservatives who see him as too lenient on illegal immigration, but as a champion of the anti-abortion movement he has credentials among cultural conservatives. Ex-Arkansas Gov. Mike Huckabee is also well respected among cultural conservatives, but he’s already been attacked as a tax raiser.

Among Democrats, New Mexico Gov. Bill Richardson has an impressive blend of foreign policy and chief executive experience. He was one of Bill Clinton’s top diplomats and has a unique relationship with North Korea’s enigmatic leadership. Sen. Joe Biden, D-Del., has a serious plan for post-war governance of Iraq that takes ethnic and religious realities into account in order to give the fledgling government breathing space.

With so many doubts planted so early, the 2008 nomination may not be as predictable as it looks at this moment.