Your Guide to Tonight's Iowa Caucuses

Tonight’s the night! At 7pm CT, Iowa Republicans will gather to cast the first votes in the Republican nominating season. Consider this your pregame report, with info from Politico, Mother Jones, and the Des Moines Register:

• The frontrunners: Polls show Ron Paul, Mitt Romney, and Rick Santorum are poised to grab the proverbial “three tickets out of Iowa.” Romney doesn’t need to win to remain the favorite for the nomination, but anything less than a respectable second will be damaging.

• Turnout is everything: If it’s high, that’s probably a good sign for Romney. If it’s low, it’s a good sign for Paul and/or Santorum—depending on where it’s concentrated. Bad weather is thought to favor Paul’s band of enthusiastic supporters.
• Location, location, location: Romney’s support is strongest in eastern Iowa, Santorum should fare well in the northwest, and Paul is hoping for turnout in college towns such as Ames. Politico highlights 10 counties to watch here.
• The battle for fourth: If either Newt Gingrich or Rick Perry can pull out a closer-than-expected fourth, they might be able to stay in the race.
• Last-minute campaigning: Romney held rallies in four cities yesterday, his most since 2008. Paul held forth in a hotel full of journalists in Des Moines, hoping to grab media buzz. And Santorum appeared with the cast of 19 Kids and Counting, the TLC reality show beloved by Iowa homeschoolers.
• Some intriguing numbers: Paul’s favorability has fallen 21 points in the past week. Only 76% of Santorum’s supporters say they’ll definitely caucus for him. Romney, meanwhile, has at some point trailed five different candidates in Iowa—and is now polling at exactly the same 18% he was at in January.

(More Iowa caucuses stories.)