Democrat Hillary Clinton would lose to all major Republican White House candidates, according to a hypothetical election matchup poll Monday, reversing her months of dominance over potential 2008 challengers.

The Zogby International poll was the latest sign that withering attacks on the former first lady were chipping away at her opinion poll leads just 38 days before the Iowa caucuses, the first party nominating contests.

In the new survey, Clinton trailed Senator John McCain 42 percent to 38 percent, former New York mayor Rudolph Giuliani by 43 percent to 40 percent and former Massachusetts governor Mitt Romney by 43 percent to 40 percent.

She also lagged behind former Arkansas Republican governor Mike Huckabee by 44 to 39 percent, and former Senator Fred Thompson by 44 to 40 percent in hypothetical general election matchups.

Clinton's top Democratic challengers Barack Obama and John Edwards however would still beat their hypothetical Republican rivals in potential 2008 contests.

In July, Clinton held a five point lead in the same poll over Giuliani, edged out McCain by two points and had a clear lead over other contenders.

A Rasmussen poll last week had Clinton also falling behind Giuliani in a hypothetical matchup of the November 2008 general election, and narrowly beaten by McCain.

If that trend holds up in other polls, the Clinton campaign could have a real crisis on its hands. And polling behind Mike Huckabee? That's pretty embarassing....

Update: Brendan Nyhan looks more closely than I did and finds those Zogby numbers less than convincing.

--Michael Crowley