[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2010/images/04/15/art.getty.crist.jpg caption="Florida Gov. Charlie Crist vetoed a far reaching education bill on Thursday."](CNN) - Florida Gov. Charlie Crist Thursday vetoed an education bill favored by state Republican lawmakers and grassroots conservatives.
The legislation, considered one of the most far reaching in the country, would have made the process of firing Florida teachers easier. Teachers and many parents opposed the bill, which would have linked educators pay to student test scores.
Some political watchers say that Crist's veto may be a signal that the governor is positioning himself as a centrist and giving up his bid against Marco Rubio for the Republican Senate nomination.
A Quinnipiac University poll indicates that Rubio, the former state house speaker and a darling with conservative activists, leads Crist by 23 points among Republican primary voters. But the survey of Florida voters, released Thursday, also indicates that Crist, if he chose to run as an independent, would hold a narrow edge in a three-way contest with Rubio and Rep. Kendrick Meek, the Democratic candidate in the race.
Sen. George LeMieux of Florida, who was appointed to his seat last year by Crist, urged the governor to sign the education bill. But LeMieux told reporters Thursday that he did not think Crist's future in the GOP is tied to his decision on the legislation.
"I don't think that him running as a Republican and what he does on the education bill are linked," he said.
Crist's standing among many Republicans was hurt by his support last year of President Obama's economic stimulus plan. Crist says his support for that measure was the right thing to do to help Florida through rough economic times.
Crist has until the end of the month to declare if he'll remain in the GOP primary or run as an independent.
"The governor is proud of his conservative credentials and stands firmly behind the principles of limited government and more personal freedom, the bedrock values of the Republican Party," Crist campaign manager Eric Eikenberg said in a statement last week.
But in the past few days, the Crist campaign has avoided questions about a possible independent bid, sparking a new round of speculation.
Asked Wednesday in an interview with the Tampa Tribune if he's considering running as an independent, Crist said "I'm not."
"Like reformers across Florida, Marco supports better pay for good teachers, as this bill would have done," Rubio Press Secretary Alex Burgos told CNN. "Once again Charlie Crist has broken his word and put his political interests ahead of doing what's best for Florida's children."
Meanwhile, Sen. John Cornyn warned Crist Thursday not to run as an independent.
"I think that would be the end of his political career as a Republican," Cornyn, the chairman of the National Republican Senatorial Committee, told Politico. "I think he's got other potential and aspirations, so I think from that standpoint, it would be a bad decision."
Last year, Cornyn actively worked to recruit Crist to make a bid for the Senate rather than run for re-election as governor. Asked if the NRSC would work to defeat Crist if he runs as an independent, Cornyn told Politico that "our job is to elect Republicans so that's what we'll do – and I don't care who it is."
(Updated at 3:15 p.m. ET with additional information)