Florida Gov. Charlie Crist's (R) decision to veto an education bill has cost him the support of his political mentor -- and that may just be the beginning.

Former Sen. Connie Mack (R-Fla.) quit as chairman of Crist's Senate campaign Thursday, citing the governor's veto in a brief resignation letter.

"As you know, I strongly disagree with your veto," Mack wrote his fellow Republican, according to the Associated Press. "Your veto I believe undermines our education system in Florida and the principles for which I have always stood."

He added, "As you can understand, I can no longer serve as chairman for your campaign for the United States Senate."

Meanwhile, state House Speaker-designate Dean Cannon (R) is reconsidering his endorsement of Crist.
 "I like the governor as a person. (But) I think that the students lost out and the teachers lost out," he told the Orlando Sentinel.

Updated at 9:38 p.m.