Rubio won't garner the GOP nomination and rightfully so. He's a fraud, the GOP token minority.
Rubio is a US Senator who has the exact same tenure Senator Obama had at the time he announced he was running for potus.
Both Rubio and Obama served in their state legislature, Rubio having been elected as the speaker of the Florida House of Representatives whereas Obama never assumed any leadership position in the Illinois State Senate.
Obama is a Harvard Law man, whereas the best Rubio could muster was a JD from "The U" (University of Miami, better known for its football program than its law school), for those who are into the pedigree of the education of politicians.
It can be argued that Rubio's political career is devoid of any accomplishment whatsoever as Obama's was, but I suspect you would not be the first to observe that fact.
The reality is that Republican voters ultimately a pragmatic lot. There was never a Pat Buchanan or Pat Robertson or Rick Santorum or Herman Cain Republican presidential nominee. The Reps back who they think are potential winners, at least going back to 1968. In 1964 they nominated a wackjob conservative who just weeks before his nomination speech in San Francisco had shamefully voted against the Civil Rights Act of 1964 (one of the few Reps to vote against the bill, as it happens), arguably the most important single piece of legislation the US Congress has ever enacted. That wackjob was hammered hard in November 1964 and the Reps have not made the same mistake since.
Nixon -- actually fairly liberal, but indeed a crook
Ford -- a political moderate
Reagan -- a political moderate (look at his record, not his rhetoric)
George HW Bush -- a political moderate
Dole -- a political moderate
George W Bush -- a political moderate
McCain -- a political moderate
Romney -- a political moderate
The mistake people make in thinking about Republicans like Nixon and Reagan is in thinking they were right-wing teabaggers. Even a 1 minute review of their actual records in office as potus (and in the case of Reagan, as governor as well) suggests the possibility that they could even be considered "liberal" by today's standards. Nixon -- a criminal, so that we're all clear, as well as a wretched human being -- created a number of environmental protection agencies and instituted wage and price controls (though soon thereafter abandoned for obvious reasons). Reagan raised taxes (both at the state and federal levels), established environmental protection agencies, expanded welfare, liberalized abortion laws before Roe v Wade, and expanded the role of size of both state and federal government.
Bush Sr was a blueblood New England Republican establishment, one of the last of his kind. Despite his plea for the Americans to read his lips, Bush did indeed raise taxes.
Dole was a dealmaker, a classic midwestern political who never met a government program he didn't like and was willing to raise taxes to make the trains run on time.
Bush Jr was the "compassionate conservative" who was, according to his critics, "soft on immigration". There's much to loathe about Bush, but he anything but the most conservative choice in the Rep field in 2000.
McCain is a "moderate" pariah in his own party and was nominated in a year when the Dem nominee was beatable.
Romney is a classic flip-flopper, but it can hardly be said of him that he was the favorite of the conservative wing of the Republican party.
All of this is to say that Reps always go who they think is the most electable candidate. It's pretty straightforward that in 2016 that means Jeb Bush. But if some reason Bush falls apart or can't get traction, it's a two man race between Walker and Rubio. It's way too early rule anything in, but Rubio cannot be ruled out.
