Amid persistent talk that he might switch to an independent Senate campaign - and indications he was making plans to leave that option open -- Gov. Charlie Crist issued a statement Thursday flatly denying it.
"To put these rumors to rest once and for all, as we have said countless times before, Governor Crist is running for the United States Senate as a Republican. He will not run as an Independent or as a No Party Affiliation," said the statement from Crist campaign manager Eric Eikenberg.
Crist blamed the rumors on the campaign of his rival for the Republican nomination, former state House Speaker Marco Rubio.
What fueled the speculation, however, was Rubio's announcement Wednesday that he raised $3.6 million for his campaign in the first three months of 2010 - a huge surge in Rubio's fundraising that Crist seems unlikely to match.
That appears to undercut Crist's last advantage over Rubio in the primary, his fundraising ability.
Meanwhile, Crist has upped his purchase of television advertising in the crucial Orlando and Tampa areas, possibly in a last-ditch attempt to see whether he can make up ground against Rubio.
The ad buy is scheduled to end April 25, leaving a few days for Crist to gauge the effects - and possibly do a poll - before April 30, the qualifying deadline for federal offices.
By noon that day, any candidate for U.S. House or Senate must file as a Republican, Democrat, minor party or no-party affiliate.
Filing for state offices including governor occurs June 14-18. Candidates can switch from one office to another, but in some cases, must offer refunds of campaign contributions if they do.
The Crist campaign won't confirm the details of the ad buy on the record.
However, the campaign has declined to comment on reports from industry sources and the Rubio campaign about the increased buy and about comments by Crist hinting that he's leaving his options open.
A Panama City television station reported Wednesday night that Crist, when asked in an impromptu interview about an independent Senate run, deflected the question instead of issuing his usual denial. The Crist campaign hasn't responded to questions about that report.
In the past, Crist has acknowledged some political allies were urging him to run as a no-party candidate because polls suggest he may be more popular among the general electorate than among his fellow Republicans.
He has denied repeatedly that he would do so.
However, he is showing no reluctance to buck his party in the state Legislature.
Crist has vetoed one bill backed as a top priority by the conservative Republicans who lead the Legislature, a bill on elections law revisions.
He has made it clear he intends to veto another priority, deregulating property insurance rates, if it reaches his desk.
He has also suggested he may oppose a third, a controversial measure abolishing multi-year employment contracts for public school teachers and requiring they be evaluated largely on the basis of student tests. That bill, knowns as the teacher tenure bill, is one of the highest priorities in the session for GOP legislative leaders and the conservatives they represent - many of whom are Rubio backers.
Running against the establishment in his own party is nothing new for Crist, and vetoing those issues might not hurt, said veteran Florida political analyst Brian Crowley.
In 2006, with party leaders backing his GOP primary opponent in the governor's race, Crist ran a campaign bashing utilities and property insurance companies for rate and premium hikes he said were profiteering.
Now, Crowley noted, teachers are rallying against the education bill, and Crist can argue that insurance deregulation would lead to rate increases.
In addition, Crist fought a highly public battle against utility rate increases prior to this session - increases halted only when Crist appointed two new Public Service Commission members.
"The Florida Legislature has inadvertently handed him some issues that could allow him to recapture his image as the candidate of the people against big business and uncaring government," Crowley said. "These are the kinds of issues that he has thrived on."
Rubio, who began his campaign as an insurgent running against a sitting governor, is increasingly looking like the establishment candidate, with Crist as the maverick, Crowley added.
"It's becoming increasingly evident that much of the GOP establishment is supporting Rubio, along with the conservative commentators."
Florida political pollster Brad Coker said it's common for political candidates to follow a surge of television advertising with a poll to gauge the effectiveness of a campaign message or to make a decision on whether to run for office.
"You run the media buy, and the day after it comes off the air, you go in the field [to take a poll], and typically a poll takes three days," he said.