Until Sen. Marco Rubio (R-Fla.) embraced comprehensive immigration reform as one of the Gang of Eight senators who wrote the bill that recently passed in the upper chamber of Congress, he had "occupied something of a sweet spot in Republican politics," says Micah Cohen at The New York Times: He was "a favorite of the Tea Party but also trusted by the establishment wing of the GOP."

Now the Republican base appears to be souring on Rubio. "The mention of his name drew boos at an anti-immigration reform Tea Party rally on Capitol Hill in mid-June," Cohen says, "and recent public opinion surveys, taken amid the debate on immigration legislation, found his favorability rating falling and his standing in 2016 Republican primary matchups eroding."

Right on cue, word comes, via The Weekly Standard, that Rubio is going to take the lead on Senate legislation that would ban abortions after 20 weeks. Rubio's office clarified that the senator is still thinking about quarterbacking the abortion bill, but he hasn't denied the week-old Weekly Standard story, and "social conservatives (who play a key role in presidential primary politics) are urging him to" lead the charge, says Greg Sargent at The Washington Post.

If Rubio says no now, "he'll need an airtight reason," says Nora Caplan-Bricker at The New Republic. But "it's painfully obvious why Rubio might want to spend a few months as the anti-abortion movement's most visible cheerleader." Sarah Palin is comparing him to Judas Iscariot for his immigration bill support, and the temptation to "endear himself to miffed conservatives and patch up any vulnerabilities on his right flank" might be too great to pass up. But even though the abortion bill won't become law, pushing for it carries some big risks, Caplan-Bricker says:

Twenty-week bans of the kind Rubio would be pushing are on dubious scientific and constitutional footing at best: They're predicated on the claim that 20-week-old fetuses feel pain, which the American Medical Association rejects; and they have been struck down or delayed by federal courts in Arizona, and Idaho, and Georgia. Even if Rubio is thinking more about his image than the bill's merits, it might still concern him that he risks alienating the moderates he will need if we wants to prevail in 2016 — and whom he went out on a limb to court during the immigration debate. [New Republic]

Losing the support of moderates isn't Rubio's only danger, say Evan McMorris-Santoro and Kate Nocera at BuzzFeed. If the past year is any indication, Republican men can't "talk about abortion without it blowing up in their face." Todd Akin, Richard Mourdock, and most recently, Rep. Todd Franks (R-Ariz.) — "it's been a long time since an abortion debate hasn't included a cringe-worthy gaffe that has diverted the focus away from the issue to a perceived GOP blindspot when it comes to communicating with the female electorate."

Taking the lead on the abortion bill will be, in many ways, "a thankless task," says Allahpundit at Hot Air. But if any Republican can come out unscathed — or even come out ahead — from becoming the public face of abortion-restriction legislation, it's Rubio:

Messaging is his thing, his big selling point. The risk of him stepping on a land mine a la Todd Akin is, or should be, small. If he wants to be the new Great Communicator, there's no better way to ace the degree-of-difficulty portion of the competition than by taking on abortion. Social cons will be watching, and he needs to win people back. No time like the present. [Hot Air]