Rudy Giuliani has a new best friend. With Mitt Romney holding twin leads in Iowa and New Hampshire and Rudy's former wingman Bernard Kerik now under indictment, Giuliani's position as the national GOP presidential front-runner seemed increasingly precarious. Enter former Arkansas Governor Mike Huckabee, whose surge in Iowa is just what the doctor ordered.

The Giuliani-Romney clash has been shaping up along familiar battle lines. Giuliani, the consensus front-runner with broad name recognition and support of the party establishment, is waging a national campaign designed to culminate in a sweep of the 22 "Super Tuesday" contests on February 5th.

Mitt Romney, on the other hand, is traveling the route of the insurgent, the dark horse. Through the mobilization of grassroots organizations and an influsion of cash, Romney hopes a surprisingly strong win in Iowa on January 3 will catapult him to victory five days later in his home base in New Hampshire. As I wrote in May, Romney is counting on the "Iowa Effect" to overturn the conventional wisdom about the inevitability of Giuliani and transform the race:

In a nutshell, the Iowa Effect is the complete upending of the predicted presidential primary landscape by a candidate's unexpected performance in the nation's first caucus. Riding a wave of adoring press coverage by a media eager to hype the tale of the underdog, the perceived winner in Iowa sweeps through New Hampshire and subsequent primary states to take (or at least seriously challenge for) the party's nomination.

The Iowa Effect is all about psychology, expectations and, more than anything else, momentum. In 2004, John Kerry's surprising win in Iowa produced a slingshot effect that took him through New Hampshire and succeeding primaries, while front-runner Howard Dean imploded within days. In 1984, Gary Hart's shocking second place finish in Iowa (he trailed Walter Mondale by 51%-16%) produced a 30 point swing and victory in New Hampshire in the span of just 8 days. In 2008, Mitt Romney is hoping to follow in their footsteps.

At it appeared to be working for Romney, that is, until last week. Governor Huckabee surged into a virtual dead heat with the former Massachusetts Governor. An ABC poll released last week showed Huckabee trailing Romney just 28% to 24%, while a new Strategic Vision survey put the deficit at only two points. (A Rasmussen poll completed yesterday actually shows Huckabee ahead 28% to 25%.)

Mike Huckabee's surprisingly strong performance reflects his own budding grassroots momentum. A charismatic campaigner, Huckabee is leveraging his second place showing at the Iowa straw poll in August. He also benefited from the departure of Sam Brownback, whose stillborn campaign was a competitor for conservative Christian votes. Perhaps more than any other factor, Huckabee, a former minister, is successfully mobilizing the evangelicals of Iowa, a group that constitutes a third of caucus-goers. (As the New York Times reports today, Romney's Mormon faith now appears to be hurting him among religious right voters in the Hawkeye state.)

However, while Mike Huckabee may deny Romney the benefit of the Iowa Effect, he may not reap the rewards, either. In New Hampshire, not a target rich environment for evangelical voters, Huckabee is trailing badly. With only 5% in a recent CNN/WMUR/UNH poll, he is running a distant fifth behind Romney (33%), John McCain (18%), Rudy Giuliani (16%) and even Ron Paul (8%). Fairing somewhat better in Michigan (January 15) and South Carolina (January 29), Huckabee has a lot of ground to make up in Florida, New York, California and other Super Tuesday states.

Right now, those states belong to Rudy Giuliani. Mike Huckabee's faith-based campaign may do nothing more than knock Team Romney off the rails.

And that makes Mike Huckabee Rudy Giuliani's best friend.