With only one week until the New Hampshire primary, and the potential of voters here to effectively eliminate some of them from the nomination battle, the stakes are high and the tone is increasingly confrontational.
"It is a dog-eat-dog, hand-to-hand combat up here," said Steve Duprey, a Republican National Committee member from New Hampshire.
In past years, New Hampshire Republicans have not followed the lead of Iowa in making their choices. Mike Dennehy, a New Hampshire-based GOP strategist, said "this year is different". "There are so many candidates ... that they are looking for help and I think Iowa did that."
That puts enormous pressure on Bush, Kasich and Christie. "Bush, Kasich and Christie have to knock Marco Rubio down in New Hampshire and steal his spot for a rationale for their campaigns to exist," said Republican strategist Steve Schmidt.
But Dennehy said Rubio's performance in Iowa also heightens the stakes for the Florida senator here. "He has to push those [other establishment] candidates down to get into a strong second place showing," he said. "Third place just isn't good enough for him. You've got to show progress and momentum."
Rubio's advisers said they were optimistic he would be able to do just that.
"Folks have figured out that Marco is a candidate who connects with voters and who closes strong," said a senior Rubio campaign official. "He's got momentum."
Rubio returned to New Hampshire yesterday, visiting a Manchester diner in the breakfast hour. He was upbeat and said he hoped to replicate his Iowa success in next Wednesday's primary.
When a supporter presented Rubio with some cigars, the son of Cuban immigrants responded playfully.
"Let's hide them, guys," he said, adding he didn't want to be a bad influence on his young children. "Maybe we'll save them for [Wednesday]," Rubio said.
Recent New Hampshire polls before Iowa showed Bush, Cruz, Kasich and Rubio in a statistical tie for second place, Christie trailing a few points back and Trump leading the field.
The finish is expected to help winnow the chaotic Republican field, affirming one or two establishment candidates as the consensus choices for party donors and other leaders when the nominating contest heads to a slew of southern states.
New Hampshire voters tend not to settle on a candidate until days before the primary.
Republicans in Iowa
Who won each key voting group: Their point advantage
Ted Cruz
• +17 Shares my values
• +12 Born-again Christian
• +9 Age 30-44
• +8 Contacted by Candidate
• +8 Attended previous caucus
Donald Trump
• +55 Tells it like it is
• +26 Outside political establishment
• +10 Top issue immigration
• +8 Can bring needed change
• +7 First time caucus-goer.