A quick guide to cut through the spin and handicap the Iowa race yourself Thursday night:

DEMOCRATS

• Hillary Clinton. A win reinforces her claim that she’s a winner. A loss raises doubts about whether she’s too damaged to win, even in her own party, let alone a general election. But she has the cash and support to fight all the way.

• Barack Obama. A win over Clinton makes him a giant-killer and gives him momentum. He has the cash and support across the country to keep going, though, even if he finishes second or a close third.

• John Edwards. Needs to win. He has spent the most time there, and it’s his best state. Might survive a close second, but doesn’t have the cash or support elsewhere to keep going after anything but a very close third-place finish.

• Bill Richardson, Joseph Biden and Christopher Dodd. Need to be within a point or two of the top three to stay in the race. Anything farther back sends them home.

REPUBLICANS

• Mike Huckabee. A win rocks the Republican Party, where elites such as Rush Limbaugh, National Review and Club for Growth are lining up to stop him. Even a close second sends him on to fight in other states.

• Mitt Romney. Must win. He has spent millions, held 235 events and led for months. Second place makes it very hard to tell Republicans elsewhere why he’s a winner.

• John McCain. Third place is a big win for a guy who barely campaigned in the state and said he would end subsidies for corn-fed ethanol. A strong third could be a launching pad to the nomination.

• Fred Thompson. Needs third to keep going till the race turns toward friendlier turf in South Carolina. Falling to fourth is a blow, making it difficult to continue.

• Ron Paul. Could sneak into double digits, enough to give him a real boost heading into New Hampshire, where he’s waiting to spend some of his Internet-raised millions.

• Rudy Giuliani. A third-place finish would be great for a guy who shunned the state and conceded that he can’t compete in farmland. Falling below Paul could finish him off.