Many did not expect Rubio to run for the Republican nomination against his mentor. "We were very surprised," said Dominic Calabro, the president of Florida Tax Watch, an independent government watchdog group. "People hoped they would be able to work it out, but that's political competition."
The two men formally became election rivals yesterday as Bush declared his candidacy at a Miami college a few kilometres from where he and Rubio both live.
"I will take nothing and no one for granted. I will run with heart. I will run to win," Bush said. His supporters waved signs that read "Jeb!" but left out his surname. He touted his record as Governor of Florida and promised that if elected "we will take command of our future once again in this country".
Having taken several veiled swipes at Bush in his own Miami announcement speech in April, Rubio yesterday welcomed him to the race.
The looming battle between the two men is more than just a drama between a former political student and master. While as many as 20 Republicans may end up trying to run for president, Rubio and Bush share a similar optimistic message and will be competing for the same voters.
Bush aides say privately that Rubio is the biggest threat to their White House hopes, far more than Clinton. Both men are presenting themselves as candidates who can appeal beyond white voters and win over parts of America's Latino population.
Rubio talks on the campaign trail about how his Cuban parents arrived in Florida in pursuit of the American dream and switches effortlessly between English and Spanish.
Bush describes how his life truly began when he met his wife, Columba, as a 17-year-old studying in Guanajuato, Mexico. He, too, speaks fluent Spanish although his is twanged with the accent of his native Texas.
There are few Hispanics in Iowa and New Hampshire, states holding early primaries, but they are expected to make up around 20 per cent of the electorate in Florida.
