Sen. Marco Rubio moved quickly Thursday to capitalize on a self-assured and quick-footed debate performance as he prepared to collide head on with Jeb Bush, his friend, neighbor and onetime political partner in Florida, in an intense and personal struggle for the support of the Republican Party's establishment wing.
Rubio's campaign expressed a guarded optimism to its supporters that it was well positioned to turn his debate success into campaign donations, which remain his most serious obstacle to defeating Bush and his massive war chest. Though Rubio has been climbing in the polls, he is still at a major cash disadvantage.
After giving a series of television interviews, he flew to Chicago for a fundraiser Thursday night.
And despite the Bush campaign's intensifying attacks on the senator's spotty attendance record and thin portfolio of legislative accomplishment, Rubio insisted that he would not shift course and begin criticizing the man he has looked up to for much of his political career.
Speaking on NBC's "Today" show Thursday morning, Rubio professed "tremendous admiration" for Bush. "I'm not running against him or anyone else," he said, adding, "I'm not going to change how I run my campaign because of what someone else decides to do. And it isn't going to change my feelings or my views about him."
Bush was in a far less generous mood after a showing Wednesday night that only seemed to magnify his flaws and raise doubts about whether he could rise to the occasion with his political future on the line. He said he would be judged on his record and his capabilities, not on his skill at sparring with other candidates.
"It's not a performance," Bush told CNN in an interview right after he stepped away from his lectern Wednesday night and prepared to get back to campaigning.
And then he jabbed at Rubio some more, calling on him to resign from his Senate seat. "The simple fact is that he has the worst attendance record in the United States Senate. Plain and simple," said Bush, who as a Miami resident is a constituent of Rubio's. "If he's not going to resign he needs to show up and vote. And I just believe that's the way we should be doing this."
An exchange at the debate over Rubio's attendance record exposed months of simmering tensions between the two — frustrations that had been largely limited to shrouded, unspecific darts on the stump in Iowa and New Hampshire, and to whisper campaigns by allies of both.
But that clash, and the comments that flowed from both campaigns after, offered a preview of the fight that Bush, Florida's former governor, and Rubio, the state's junior senator, are likely have as the Iowa caucuses approach.
It is a fight that Bush and his allies see slipping from their grasp.
Bush and the "super PAC" working on his behalf, Right to Rise, have now decided to engage with Rubio directly, as they come to terms with what their declining poll numbers and exasperated supporters have been saying for some time: The higher Rubio rises, the more difficult it will be to improve Bush's fading prospects.
While the senator, for now, has been able to take a highroad approach, he has found it impossible to ignore the intensifying barrage of attacks, not just from the Bush apparatus but from Democrats as well, a sign there is a consensus forming that Rubio is the emerging favorite with the Republican Party's traditional base. But his graciousness is also self-interested; he and his team know they cannot afford to alienate the Bush supporters and donors they are now trying to poach.
In interviews Thursday, Rubio said that he hated missing so many votes, suggesting that he was stung by criticism from a major Florida paper and others who have accused him of spending too much time away from his day job.
"But here's what I would hate more," Rubio told CNN, adding that he would not want to wake up the morning after the election and discover "that Hillary Clinton has been elected president of the United States."
The attacks are only going to keep coming. Right to Rise started a Twitter feed, "@isMarcoWorking," that mocks Rubio's absences from the Senate while he has been campaigning for president. He has missed about a third of the votes this year, giving him the worst attendance record in the Senate. (However, other senators who ran for president recently, like Sen. John McCain of Arizona and John Kerry of Massachusetts, racked up higher rates of absenteeism than Rubio.)
From Boulder, Bush heads to New Hampshire for a day of campaigning and then to Florida for a high school football game in a community struck hard by a hurricane when he was governor. Rubio will leave Chicago to travel to Iowa for a full day of rallies and town hall-style meetings with voters. The two candidates will meet Saturday at the state fairgrounds in Des Moines at a forum with several other contenders hosted by the Iowa Republican Party.
The debate was also notable for the strong showing by Sen. Ted Cruz of Texas, who drew applause for his pointed attacks on the news media. The campaigns of Rubio and Cruz, who wants to expand his appeal with the party base of evangelicals and conservatives, are hoping their candidates' performances will propel them from their single-digit showings in early nominating states like Iowa and New Hampshire, which vote in just three months.