Rubio has staked out a position in Syria that is in one way all his own, and in another, simply a middle ground between two competing camps. The question now is whether that will help or hurt his standing within the party.
Heading into this week's debate over whether to launch a military strike against the Syrian government in retaliation for the alleged use of chemical weapons, there was uncertainty about where Rubio would come down. On the one hand, he has called for more intervention (though not in the form of a military strike) in Syria; on the other, support for a strike would align him with a Democratic president at a time when he is seeking to repair his image among conservatives after a months-long push for a sweeping immigration reform bill. And it would make him stand out like a sore thumb in the potential 2016 field.
"A yes vote would be a contaminant for any Republican running for president," said veteran Republican strategist Ed Rogers. "There are valid good reasons to support the resolution but if you are explaining, you are losing. No way a 2016 contender should support this."
A glance at where the other potential presidential hopefuls stand tells you all you need to know. Sen. Rand Paul (R-Ky.) has been arguably the most vocal opponent of military intervention in the Senate. Sen. Ted Cruz (R-Tex.) does not favor a strike, either, nor does former senator Rick Santorum R-Pa.). Even New Jersey Gov. Chris Christie (R), who has demonstrated more hawkish leanings on national security, has been silent.
Rubio's decision came against the backdrop of an emerging debate over foreign policy in the Republican Party, driven most publicly by the Christie and Paul, who have sparred over the utility of government surveillance efforts. So in voting "no," is Rubio joining the ranks of Paul and the growing bloc of libertarian-leaning Republicans who are highly skeptical of U.S. involvement in overseas conflicts?
No. Rubio made that clear in forceful and nuanced remarks explaining his vote.
In a speech that is likely to be quoted again and again in the run-up to 2016, Rubio explained his vote as the result of being unconvinced that the proposed military action would accomplish much, not as a signal that Syria doesn't matter for U.S. interests or a sign the U.S. shouldn't meddle at all.
"While I have long argued forcefully for engagement in empowering the Syrian people, I have never supported the use of U.S. military force in the conflict," Rubio said. "And I still don’t. I remain unconvinced that the use of force proposed here will work. The only thing that will prevent Assad from using chemical weapons in the future is for the Syrian people to remove him from power."
What Rubio said at the end of his speech was even more interesting, and sure sounded like a clear effort to put daylight between himself and the non-interventionist wing of the GOP.
"Let me close by recognizing that there is a movement afoot in both parties to disengage the United States from issues throughout the world," he said. "It is true, we cannot solve every crisis on the planet. But if we follow the advice of those who seek to disengage us from global issues, in the long run we will pay a terrible price."
Rubio, Rogers said, is presented with the opportunity "to vote against this and at the same make the argument that it doesn't make him an 'isolationist.' He could give cover to other Republicans from that charge and label."
At the same time, Rubio's not exactly aligning himself with the leading hawks in his party, either.
As the Florida Republican sat at his spot on the dais and delivered his remarks Wednesday, only one Republican senator stuck around to listen. Sen. John McCain (R-Ariz.) stood just a few paces away watching his younger colleague, visibly scowling at times. He turned and walked out of the room quickly as Rubio concluded his remarks.
— Ed O'Keefe contributed to this post