By Steve Holland and David Adams
MIAMI (Reuters) - Republican Marco Rubio presented himself as the leader of a new political generation and the most viable alternative to Democrat Hillary Clinton as he entered the 2016 White House race on Monday and drew a contrast with his mentor and expected opponent Jeb Bush.
Rubio cast himself as a fresh face who could move the country past the Bush and Clinton dynasties that have led American politics for decades and are seeking to again.
"The time has come for our generation to lead the way to a new American century," Rubio, 43 and the son of Cuban immigrants, told a cheering crowd at Miami's Freedom Tower, where thousands of Cuban exiles fleeing the Communist-run island in the 1960s were first registered by U.S. authorities.
Cheers of "Marco, Marco" rang out from the jam-packed audience when Rubio, a first-term U.S. senator of Florida, announced his candidacy.
"Before us now is the opportunity to author the greatest chapter yet in the amazing story of America. We can't do that by going back to the leaders and ideas of the past," Rubio said.
In a not-so-subtle swipe at Clinton, Rubio referred to her as "a leader from yesterday" who wants to take the country "back to yesterday." His entry into the 2016 race came a day after the 67-year-old Clinton declared her candidacy.
Rubio's decision to forgo a run for re-election to the U.S. Senate and to compete against Jeb Bush for the presidency has been the talk of Florida. Bush, who has not yet declared himself a candidate, was a big supporter of Rubio when he was the Florida governor and Rubio was the speaker of the House of Representatives.
Aides to both men say there has been no bad blood between them, but both see a path to the presidency and are willing to compete against each other to get there.
Rubio told ABC News, "I'm not running against Jeb Bush and I hope he's not running against me."
But, he said, the country needs "a Republican Party that is new and vibrant and that understands the future, has an agenda for that future, and I feel uniquely qualified to offer that."
VOTER SPLIT ON RUBIO VS BUSH
Both men are trying to position themselves as establishment candidates with conservative street credibility. Both want to expand the appeal of the Republican Party to include Hispanic-Americans.
Rubio, who rode the anti-establishment tea party movement in 2010 to the national prominence, is a gifted communicator who made much of his immigrant roots at his campaign announcement, talking about how his father worked as a bartender and his mother as a maid and cashier.
His campaign announcement focused on how to help middle-class Americans and also focused on foreign policy, which is his strength based on his work on the Senate Foreign Relations Committee.
But Bush carries more experience after eight years as Florida governor and his close-up view of the presidencies of his father and brother.
And many Republicans who feel President Barack Obama is out of his depth worry that Rubio has only the same amount of time in the Senate as Obama had when he was first elected.
"I encourage Marco to run but I am backing Jeb as I think he's the best prepared to be president," Florida Republican strategist Justin Sayfie said.
Many Florida Republicans would prefer that Rubio run for re-election to the Senate, a point Rubio specifically rejected in his speech.
"I have heard some suggest that I should step aside and wait my turn. But I cannot, because I believe our very identity as an exceptional nation is at stake, and I can make a difference as president," Rubio said.
Rubio is the third Republican to formally announce a White House bid, following Senators Ted Cruz of Texas and Rand Paul of Kentucky. Rubio's support registers in single digits in opinion polls of the likely contenders in a Republican presidential field. One concern is whether he can raise enough money.
Norman Braman, a Miami car dealer and former owner of the Philadelphia Eagles football team, said he would be making a "substantial contribution" to Rubio, and others would too.
"He is first and foremost cognizant of the problems that people are having today in being able to buy a home and educating their children," Braman said. "He's lived through the problems himself."
Jorge Luis Lopez, 53, a Cuban-American lawyer, said he respects Bush but he could not match Rubio's grassroots activism and inspirational rise.
"As much as I would have it be Jeb he doesn't offer the same transcendental history that Marco does," Lopez said.