Republican Marco Rubio announces bid for presidency in Miami

U.S. Senator Marco Rubio of Florida urged voters on Monday to make a "generational choice" for new leadership that is not mired in the policies of the past, as the Republican announced he will enter the 2016 race for the White House.

Rubio, 43, presented himself as a fresh face who could find new approaches needed for the United States to solve its challenges and compete in a global economy, and criticized Democratic front-runner Hillary Clinton as a leader stuck in "yesterday."

"The time has come for our generation to lead the way to a new American century," Rubio 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.

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Rubio, a son of Cuban immigrants who rode the anti-establishment Tea Party wave of 2010 to national prominence, said voters could not choose leaders who were stuck in the ideas of the past.

"We must change the decisions we are making by changing the people who are making them," he said. "This election is not just about what laws we will pass. It is a generational choice about what kind of country we will be."

Without naming Clinton, who announced her candidacy on Sunday, Rubio made reference to "a leader from yesterday" who had "announced her campaign yesterday."

"But yesterday is over, and we are never going back," he said. "We Americans are proud of our history, but our country has always been about the future."

Rubio's relative youth contrasts with Clinton, who is 67 and has been on the national political scene for more than 20 years, initially as first lady and later as a U.S. senator and then secretary of state.

Rubio's call for new leadership also could be seen as an attempt to step out of the shadows of his political mentor, former Florida governor Jeb Bush, the son and brother of former presidents.

Rubio likely will compete for donors and endorsements with Bush, who has been lining up support for a White House bid but has not yet formally entered the race.

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. But aides believe Rubio, who was on 2012 nominee Mitt Romney's short list for vice president, will rise when voters take a closer look at him.

Rubio will be competing for the limelight with Clinton, who grabbed worldwide attention with the declaration of her candidacy for the Democratic presidential nomination on Sunday.

Clinton will hit the campaign trail in Iowa on Tuesday and Wednesday. Iowa holds the kickoff contest in the parties' presidential nominating process early next year.

While he owes his success to the Tea Party movement, Rubio also has drawn support from more traditional party elements as well as the libertarian-leaning network assembled by billionaire brothers Charles and David Koch.

His effort to overhaul the United States' immigration system could be a sticking point for Republican conservatives, many of whom view any move to grant legal status to undocumented workers as "amnesty."

Rubio worked with Senate Democrats to pass a sweeping immigration reform bill in 2013 that would have bolstered border security and guest-worker programs with a pathway to citizenship for those already in the country illegally. The measure died in the Republican-controlled House of Representatives.

Rubio now says any immigration reforms must be passed piece by piece, with border security coming first, a position more in line with other Republican lawmakers. But he talks frequently about the central role immigrants play in revitalizing the United States.

Rubio also called for a muscular foreign policy, portraying himself as the Republican most ready to handle threats to America.

He highlighted his biography and the backgrounds of his father and mother and their journeys to the United States.

"I live in an exceptional country where even the son of a bartender and a maid can have the same dreams and the same future as those who come from power and privilege," he said.