The six Republican candidates vying to win the Iowa caucuses — or in some cases avoid defeat on a campaign-ending scale — have only hours left to make their cases to the state's voters, 40 percent of whom are still undecided, according to some polls.
Mitt Romney, Ron Paul and the late-surging Rick Santorum are believed to make up the top tier of candidates.
For Newt Gingrich, who has faded in recent weeks under a barrage of negative attacks, Rick Perry and Michele BachmannMichele BachmannNo-shows at GOP convention Clinton camp: Trump VP pick is 'divisive,' 'unpopular' Lobbying world MORE, the results must provide some straw robust enough to cling to as the campaign moves on to New Hampshire, South Carolina and Florida before the end of the month. (A seventh candidate, Jon Huntsman, is not competing in Iowa, focusing his energies on New Hampshire instead.)
Romney says he is the best candidate to defeat President Obama in November.
Ron Paul argues that choosing any contender other than him would amount to a futile and wrong-headed endorsement of "the status quo."
Rick Santorum tells conservatives that they should pick a stalwart of their cause, rather than settling for an ostensibly more electable, more centrist candidate who could, at best,"win a Pyrrhic victory" over Obama.
Campaigning on caucus day itself is always a tricky proposition, the candidates' desire to fire up their supporters being countered by a fear of distracting from the more important get-out-the-vote work that often characterizes the final hours.
Romney begins the day with a breakfast-time event at Des Moines's Temple for Performing Arts. He has no more events planned until his election-night party begins at a downtown Des Moines hotel. Paul, too, has only one public engagement scheduled — a speech to students at a West Des Moines high school — before his own election-night event. Santorum had no public events listed on his schedule, aside from his party at the conclusion of the evening.
The caucuses begin at 7 p.m. CT/8 p.m. ET. A trickle of results, especially from the least populous precincts, could start coming in within 30 minutes. The trickle should become a flood by 9 p.m. CT/10 p.m. ET or shortly afterward. All 1,774 precincts in the state will hold a caucus.
The weather can play a critical role in turnout, and in the result. The forecast for Des Moines on Tuesday is favorable, albeit with a low temperature of 30 degrees.
A victory for Romney could set him well on his way to claiming the nomination. Speaking briefly to The Hill on Monday, he said he expected the results to give him "a good send-off" into the rest of the process. (His campaign has insisted that remarks Romney made during his speech at the same event, in Marion, when he said "we are going to win this thing," referred to the nomination, not the Iowa contest in particular.)
Perry's campaign on Monday released his schedule for Wednesday to Friday, showing him campaigning in South Carolina on all three days. The schedule's release seemed timed to send a message that Perry would not be withdrawing irrespective of the results in Iowa.
Bachmann will also be in South Carolina on Wednesday. South Carolina does not vote until Jan. 21, but both Perry and Bachmann view it as a much better fit for their brand of conservatism than New Hampshire, which holds its primary on Jan. 10.
Romney will be in New Hampshire on Wednesday and Thursday morning before departing for a quick South Carolina trip. The plans of Paul and Santorum for the rest of the week have not yet been released.
President Obama will not be letting Republicans have all the limelight. He is a candidate in the Democratic caucuses Tuesday evening, without serious opposition. At 7:15 p.m. Iowa time, he will participate in a video teleconference with Iowa caucus attendees, according to the White House.
The relatively low-key nature of the video conference will be a far cry from the memorable night four years ago when Iowa Democrats handed Obama a victory over Hillary ClintonHillary Rodham ClintonSanders says leaked DNC emails don't change his support for Clinton Sanders wanted Elizabeth Warren as Clinton's VP Trump up in battleground states after convention, leads Clinton MORE, propelling him down the road to the White House.
The mere fact that Obama is making time for Iowa on Tuesday is also a reminder, however, that the Hawkeye State is expected to be a battleground once again in November's presidential election.