Marco Rubio has been the junior senator from Florida for barely two years, but he's already considered a likely 2016 presidential contender.
The 41-year-old Republican's political star rose still higher this week when he joined a bipartisan group of senators offering a path to citizenship to millions of unauthorized immigrants.
It's the latest in a series of shifts on immigration by Rubio, the Miami-born son of Cuban exiles who ran for Senate in 2010 as a Tea Party-backed conservative, rejecting a so-called earned path to citizenship for undocumented immigrants, which at the time he called "code for amnesty."
But Rubio is no longer calling it amnesty.
"This allows people the access to make their status at this moment legal, if they meet certain benchmarks. And, ultimately, to have access to the regular opportunity that anybody else in the world would have, to get a green card," Rubio said this week, in joining other senators to announce the framework of their plan. "And obviously, once you get a green card, you're three to five years away from being a citizen."
In a brief interview, Rubio called his reason for joining the bipartisan effort simple: "It's important for our country. It's important for Florida. And I just want us to handle it in a way that's permanent and responsible."
Others smell political opportunism.
"He appears to be different things to different people," says Rollins College political scientist Richard Foglesong, a fellow Floridian. "And if one looks back over his career, he's done a pretty good job of being what it is that people want him to be."
But another Florida political observer sees Rubio's current position as a return to his roots on the issue of immigration.
"When Marco was in the Florida House, he was what you consider to be progressive today on immigration issues," says Steve Schale, a Democratic consultant who watched Rubio's career in the state Legislature. "He fought for things like in-state tuition for children of illegal immigrants. In a lot of ways, I think this is Rubio making the full circle back to where he was on these issues 10 years ago."
Rubio's move may also give conservatives needed political cover to join him.
"I think he'll be a great voice on immigration reform," says Sen. Lindsey Graham, R-S.C., who's part of the bipartisan group. "He's a good solid conservative, rising star in our party. I think it will help our chances of success greatly."
But an immigration overhaul with a path to citizenship can be a tough pill to swallow for many conservatives. Emory University political scientist Merle Black says it's also a big risk.
"What Rubio's done is to put himself in a position where he has to explain his position, and he'll have to do this over and over again," says Black.
For his part, Rubio waged a charm offensive all this week with conservative talk show hosts. He told Rush Limbaugh that since Democrats are pushing for immigration changes, conservatives had to be in the mix as well.
"I know this is a tough issue. I do. I know why people are uncomfortable about it," Rubio said during an interview with Limbaugh. "It doesn't feel right, to in some instances, to you know, allow people who have come here undocumented to be able to stay. I know that for some people they are uncomfortable with that notion. This is a tough issue to work through."
Limbaugh seemed charmed: "What you are doing is admirable and noteworthy. You are recognizing reality. You're trumpeting it. You're shouting it."
Yet William Gheen, president of the advocacy group Americans for Legal Immigration, says he feels betrayed by Rubio.
"Marco Rubio, you will never be president of the United States of America," says Gheen. "Trying to stand up for illegal alien invaders instead of American citizens is a campaign killer, and Marco Rubio's name is now synonymous with a Republican turncoat trying to push amnesty for illegal immigrants."
Such pushback, says Democratic consultant Schale, should not surprise Rubio.
"He's a pretty bright guy. I think he understands the risk he's taking here," says Schale. "But he's also ambitious, and I'm sure he's made the calculation that in the long run, this is the right place to be."
Much may depend on how many of Rubio's fellow conservatives think it's the right place to be.