Sen. Marco Rubio, the 40-year-old rising star of the Republican Party and among top contenders to be Gov. Mitt Romney’s running mate, is trying to rebrand himself from a right-wing Cuban-American politician to a center-right Hispanic one.

That’s the impression I got after interviewing him at length on immigration and U.S.-Latin American relations last week.

During the interview, Rubio — who, if picked to be on the ballot in November would become the first Hispanic on a presidential ticket — stayed a prudent distance from the most extreme foreign policy stands of his hard-line Republican colleagues in Congress.

On immigration, Rubio, opposes President Barack Obama’s proposed Dream Act that would give a path to citizenship to more than 1 million college-bound students who were brought to this country as children by no fault of their own. But in the interview, he stressed his new proposal to draft a bill that would give these youths legal residency, but no citizenship. He said “a little bit more compassion is needed” for these undocumented youths.

Asked whether Romney hasn’t alienated Latinos by wholeheartedly embracing Arizona’s anti-immigration law and calling for the “self-deportation’’ of undocumented residents — a euphemism for what many see as making their lives impossible in order to force their departure — Rubio made various verbal pirouettes to avoid criticizing his party’s presumptive nominee.

He said that Romney’s statements on immigration during the primaries “reflect the legitimate frustration with a runaway immigration problem,” and added that the media have not placed enough attention on Romney’s “robust support for legal immigration.”

When pressed on the Republicans’ anti-immigrant stands, Rubio admitted that “there are minority voices within the Republican party that have used a very negative rhetoric.” He added that his alternative Dream Act proposal “is a great opportunity for the Republican Party to start taking a positive agenda on the immigration issue.”

Rubio is expected to present his alternative Dream Act around June, at about the time when he comes out with an autobiographical book, and before Romney is expected to make his decision on a running mate.

Right now, Romney has a big problem with Latino voters, which has helped fuel speculation about Rubio’s vice-presidential nomination. Obama leads Romney by a whopping 67 percent to 27 percent among Latino voters in the most recent Pew Research Poll.

Asked whether he agrees with a recent proposal by his conservative Republican colleagues in the House calling for adoption of “counter-insurgency tactics” to combat an alleged “terrorist insurgency” in Mexico, Rubio told me that he is not familiar with that bill, but that he would not brand Mexico’s drug cartels as “terrorists” because they do not have an ideological agenda.

On a similar bill by House conservative Republicans to cut by 20 percent the U.S. funding to the 34-country Organization of American States if that group keeps failing to condemn anti-constitutional measures by Venezuela and Nicaragua, Rubio said he was “ not ready to ask for a reduction of U.S. funds yet, but I do have many concerns about the OAS.”

Asked about his House conservative colleagues’ call to have the State Department include Venezuela among its list of “terrorist nations,” Rubio told me: “I am not prepared to say that now.”

He explained that Venezuela will hold elections in October, and Washington should await their outcome before taking drastic measures. If Venezuela’s anti-democratic trends and ties to Iran continue, “I think it’s something we will have to give serious consideration to,” he said.

My opinion: Rubio is a smart, charming and smooth politician who has embraced horrendous positions on immigration and other issues in the past. Now, he is trying to become a Hispanic politician with national appeal who can help Romney solve his problem with Latino voters, and is shifting somewhat to the center.

That’s great. But before I conclude that I like the new Rubio much better, I would like to see whether — in addition to using a more compassionate rhetoric on immigration — he can sway a significant number of Republicans into voting for a meaningful Dream Act bill.

If he can break the current congressional deadlock on immigration, Rubio will be much more than a charmer. He will become a game changer, and a Washington superstar with real substance. We will know that very soon.