By Lisa Mascaro, Tribune Washington Bureau (TNS)

MIAMI — Three years ago, Sen. Marco Rubio was heralded as the Republican Party’s future.

After the GOP’s stinging 2012 presidential loss, strategists prescribed the charismatic, young Tea Party favorite as the antidote to a fractured party — someone who could even expand the base by attracting Latino voters.

He so dazzled the 2012 Republican National Convention when he introduced Mitt Romney that some called the conservative a transformational candidate not seen by Republicans since Ronald Reagan.

But despite the cheers that greeted the 43-year-old Florida senator as he announced his presidential bid Monday, the early buzz has faded. And after a political misstep over immigration reform, Rubio finds himself just another name in an increasingly crowded field of 2016 presidential rivals who have chipped away at what were once his strongest assets.

Former Gov. Jeb Bush, with his unmatched fundraising juggernaut, knocked off Rubio as the GOP establishment favorite. Sen. Ted Cruz of Texas is stealing the hearts of evangelicals and Tea Party activists. Wisconsin Gov. Scott Walker is the new fresh face.

Now seen at best as a sleeper candidate, Rubio needs to reignite the excitement that once led the party to view him as a front-runner.

On Monday he tried to do exactly that. In front of nearly 1,000 supporters, he evoked his youth and his parents’ immigration from Cuba, displaying the skills that make him one of the party’s more gifted communicators.

“Now, the time has come for our generation to lead the way toward a new American century,” he told the crowd at Freedom Tower in downtown Miami, known as the Ellis Island of the South for welcoming Cuban exiles.

Though some have questioned whether Rubio, a freshman senator with a young appearance and a thin legislative record, has the experience or commanding presence Americans expect of their president, Rubio presented his age as a benefit, drawing a contrast with older rivals such as Bush, 62, and the Democratic front-runner, Hillary Rodham Clinton, 67.

“Just yesterday, a leader from yesterday began a campaign for president by promising to take us back to yesterday,” he said, referring to Clinton’s Sunday campaign kickoff.

“While our people and economy are pushing the boundaries of the 21st century, too many of our leaders and their ideas are stuck in the 20th century,” he said, adding that America won’t succeed by “going back to the leaders and ideas of the past. We must change the decisions we are making by changing the people who are making them.”

Rubio’s backers are confident he can repeat the kind of come-from-behind victory that propelled him to the Senate in 2010.

“He’s proven time and time again he’s the comeback kid,” said Nick Iarossi, a Florida lobbyist for casino mogul Sheldon Adelson, a top-ranking Republican donor. “Any one who would underestimate him does so at their peril.”

But Rubio — No. 2 in a 2012 national presidential survey of Republican voters — has languished in fifth or sixth place behind Bush, Walker and others in recent polling.

Rubio stumbled badly in 2013 by first proposing, and then abandoning, a sweeping immigration reform plan, which alienated its advocates.

Many conservatives haven’t forgiven Rubio for joining Senate Democrats in passing the now-dead bipartisan plan that would have created a path to citizenship for those in the country illegally. Critics blasted it as “amnesty.”

“It’s a wart on an overall positive story,” said Michael Needham, chief executive of the conservative Heritage Action for America, the political arm of the influential Heritage Foundation think tank.

Rubio has tried to move on from the issue, saying he miscalculated Americans’ desire to first tackle border security, which is of huge importance to his party’s most loyal voters. But as he becomes the third official Republican candidate for 2016, the issue is certain to follow the man who dreams of being the first major party Latino presidential nominee.

At Monday’s event, he gave only passing mention to the need to “modernize” immigration laws, calling for a more robust military, tax reform, reduced government spending and the repeal of the Affordable Care Act. At one point, he spoke in Spanish, offering an inspirational quote from his late father.

Rubio has amassed a strong campaign team, many coming from Mitt Romney’s 2012 presidential bid. To bolster his policy credentials, the freshman senator recently rolled out a series of position papers and a new book, American Dreams, in which he takes his own party to task for what he said was outmoded policy thinking.

“He’s the only Republican candidate that is acceptable to all branches of the Republican Party — the establishment groups, the Tea Party groups, the libertarian groups,” said billionaire auto dealer Norman Braman, who has pledged substantial backing for the campaign.

Rubio’s only-in-America story is expected to weigh heavily in the campaign. “In many countries, the highest office in the land is reserved for the rich and powerful,” Rubio said Monday. “But 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.”

Rubio has credited his strongly conservative views to childhood talks with his anti-communist Cuban grandfather. He sided with defense hawks last month in seeking to boost Pentagon spending, parting ways with two 2016 candidates, Cruz and Sen. Rand Paul, R-Ky., who voted against the budget.

In recent months, Rubio’s GOP rivals have shored up their pathways to the nomination, luring away constituencies that Rubio would need to win. The presumed entry of Bush makes it particularly difficult for Rubio to even capture his own state of Florida, where Bush’s ties are deep.

And his moves on immigration have dimmed his appeal to Latino voters — one of the main reasons that party leaders once found him so attractive.

In 2013, when Rubio pushed his immigration plan, 54 percent of Latino voters were likely to consider him for president, according to the polling firm Latino Decisions. But when told that Rubio had switched course on the immigration effort, 65 percent said they weren’t likely to give him a look.

Since then, Rubio has attacked President Barack Obama’s executive actions deferring deportations — which have cost him more support.

“He’s going to have a very hard time getting back to his high mark,” said Matt Barreto, a University of California, Los Angeles political science professor and co-founder of Latino Decisions.

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