In politics, they call it “Big Mo,” the momentum that comes from a win and the opportunity to take that momentum into the next primary.

Both Barack Obama and Mike Huckabee left Iowa with “Big Mo” driving their campaigns. Polls taken in New Hampshire right after the Iowa caucuses show both candidates gaining and the campaign fortunes of New Hampshire front runners Hillary Clinton and John McCain sliding.

Clinton’s lead in New Hampshire is down to four points and is expected to shrink even further by the first of next week. Some polls show Obama ahead. John Edwards, second in New Hampshire polls before Iowa, is now third and dropping.

“This is shaping up as a two-candidate race between Obama and Clinton,” admits a dejected Clinton strategist. “Obama has the edge right now. If Edwards fails to score in Iowa and South Carolina he’s out.”

While Obama’s momentum threatens to sweep other challengers aside, Huckabee’s victory is actually seen as more of an advantage to McCain. The former shooting star called Fred Thompson is now plummeting to earth. The actor-politician promises to hang in for the long haul but he’s short on cash and support and is, for all practical purposes, skipping New Hampshire.

Notes The Wall Street Journal about Thompson:

As a noncandidate, Fred Thompson could command the Tonight Show with Jay Leno to deliver his political message. Now, the would-be savior of the conservative coalition can barely get coverage from the Des Moines Register.

The Register’s decision not to staff Mr. Thompson’s campaign in the final days before the caucuses and rely instead on wire reports is just one of many signs that his presidential bid has skidded toward the margins amid the ice and snow of Iowa and New Hampshire.

Ron Paul’s fifth place showing in Iowa was less than his enthusiastic supporters wanted but they still predict better things ahead for the long-shot candidate.

Notes Wired:

Thousands of hours of YouTube videos, dozens of Meetup groups, an airborne advertising campaign and a rabid internet following all weren’t enough to boost Texas Republican Ron Paul up to third place at the Iowa caucuses Thursday night.

But it was enough to place the congressman and presidential hopeful in fifth place, beating out New York City Mayor Rudolph Giuliani.

And it was enough for the campaign as well its supporters (and detractors of those supporters) both online and off.

“This campaign is just beginning, and we are starting off better than anyone in the ‘mainstream’ media imagined,” wrote Lew Moore, Paul’s campaign manager in a message to supporters on their site.

“I was partly encouraged and partly disappointed — my desire was that he would finish ahead of John McCain and frankly ahead of Fred Thompson,” says Skip Cook, a lifelong Republican, Paul supporter and loan officer in Little Rock, Arkansas. “I think I was too optimistic about how the state of Iowa would react to him.”

If enthusiasm and optimism could vote, Ron Paul would be leading the GOP pack but he needs a better showing in New Hampshire to turn that optimism into reality.

Meanwhile, former New York Mayor Rudy Giuliani’s lay-back-and-wait strategy is looking more and more risky. By the time the South Carolina and Michigan primaries are over the GOP race could turn into a two man battle between Huckabee and McCain with everyone else outside looking in.