SEN. MARCO RUBIO, the Florida Republican in whom some GOP activists have invested presidential hopes for 2016, has seized on the issue of immigration, hoping to stake a claim to leadership in the coming national debate and to revive Republicans’ dismal standing among Hispanics. What’s striking about his plan, outlined so far in the media rather than in legislation, is that it appears to depart from President Obama’s own approach in details, not principles.

Both agree on the logic and inevitability of amnesty for 11 million undocumented immigrants (though neither uses the word “amnesty”). Now they’re just arguing over the price those immigrants should pay as a condition for remaining in America.

Specifically, while both envision a pathway to citizenship, they appear to part ways on how tortuous it should be. Mr. Obama would have illegal immigrants pay a fine, learn English and clear criminal background checks before “earning” citizenship. Mr. Rubio would have them jump through roughly the same hoops — but only to qualify for an interim legal status, from which they could emerge some time later by applying for green cards as a path to citizenship. Same endgame, different timetable.

In fact, nothing in Mr. Rubio’s proposal is terribly novel; it’s a tweaked version of what many Democrats have wanted for years. It includes tough border controls; employment verification; a workable guest-worker program; and more visas for highly skilled science, tech and engineering graduates. Mr. Rubio even said that he would not insist on chopping his proposals into separate bills, in recognition that the White House and immigration advocates will accept nothing short of a package deal.

But the centerpiece of Mr. Rubio’s plan, a pathway to citizenship with stages, is new for him. As a candidate for the Senate in 2010, he denounced amnesty for immigrants without papers. His position now, labels notwithstanding, represents a shift. It also requires guts.

Conservative Republicans in Congress and statehouses, in thrall to radio talk show bloviators, have vilified any solution short of mass deportation as a sellout that rewards scofflaws. On immigration, nativist extremism infected the Republican mainstream years ago. Disinfection will not occur simply because a freshman senator has crooked his finger and asked the party to follow.

There are encouraging signs. Rep. Paul Ryan of Wisconsin, the Republican vice presidential candidate last fall, has endorsed Mr. Rubio’s approach. Other prominent Republicans, recognizing that Mr. Obama’s 71 percent share of the fast-growing Hispanic vote spells long-term electoral doom, are urging a change. There is a growing realization in the party that a new tone on immigration would constitute a olive branch to Hispanics.

Mr. Rubio, one of just three Hispanics in the Senate, has made clear he’s willing to lead. The question in the coming months is whether his party’s mainstream, in Congress and state capitals, can be coaxed toward moderation.