First is momentum: whether Rubio and Cruz can maintain it, and whether Trump can regain it. Second is who will attract the GOP voters who support the floundering candidates as they quit or become obvious no-hopers but refuse to quit.

The tweet resurfaced on Monday night after the caucus results. Online, one headline read: "Iowa Caucuses: Cruz Wins GOP Race; Clinton Defeats Sanders".

Asked before a rally in Milford, New Hampshire, on Tuesday evening if he planned to change his campaign strategy, he told a news conference he felt confident in his methods, but he was adding more town hall-style events.

Indeed, the once-unthinkably-small margin the former first lady, senator and secretary of state held over the self-declared democratic socialist suggested the Democratic contest is headed toward a protracted fight between the party's pragmatic and progressive wings.

Former Maryland Governor Martin O' Malley received less than 1 percent of the vote and was rewarded 7.61 state delegate equivalents, said the newly released results hours after O'Malley dropped out of the race.

Susan Duprey, who served as chief of staff to Ann Romney, Mitt Romney's wife, in 2011 and 2012, announced her support for the Florida senator on Tuesday night. Everyone knew the contest between Hillary Clinton and Bernie Sanders would be close, and it was.

Sanders believes it is very possible that his campaign won the popular vote in Iowa, even though Clinton won a few more delegates than he did.

Polls show well over half of Republican voters are undecided in New Hampshire.

On the Republican side, businessman Donald Trump is looking to rebound after a second-place finish in Iowa that marked a humbling blow to the boastful real estate mogul.

Cruz said after the results: "This is a victory for the grassroots, a victory for the greatest conservatives across Iowa".

Trump did receive some good news the day after his disappointing night in Iowa.

For his part, when pressed about whether he could stay in the race should he not perform that well in New Hampshire, Bush brushed the idea aside.

Next up for U.S. presidential candidates from both parties is the tiny New England state of New Hampshire, which votes next Tuesday. Ted Cruz won the caucuses, than he would have believed back when he launched his campaign in June.

"I'm pro-life. He told everybody I was pro-choice".

Sanders has an 18 point lead in New Hampshire polls, with the primary a week away. Because of the way the process works in the Democratic Iowa caucuses, there is no mechanism for a recount.