Marco Rubio is a regular topic of conversation during my weekly “Ask Aaron” live chat (Tuesdays at noon!). And invariably, when his name comes up, it's about his political potential. Rubio is a guy whom people like me consider the future of the Republican Party. We see flashes of real political ability — even brilliance — that make us wonder what he could become. Others think that Rubio is oversold as a politician and that there's just not a whole lot of “there” there, despite the media's fascination.

Sometimes I sympathize with that latter point of view. Times like Monday morning.

Rubio just announced that he will support President Trump's nomination of ExxonMobil chief executive Rex Tillerson for secretary of state despite some very clearly stated reservations. In a Facebook post, Rubio assured us that he still has those reservations, but despite them, “I will support Mr. Tillerson’s nomination in committee and in the full Senate.”

Rubio seemed to have some very principled objections to Tillerson. The senator from Florida, after all, is a foreign policy hawk who has long been wary of Russia and its president, Vladimir Putin. And Tillerson's ties to Russia — and how that might play into Trump's expressed desire to work with Russia — would give anybody like him pause. Hawkish Sens. Lindsey O. Graham (R-S.C.) and John McCain (R-Ariz.) were also reluctant, although they eventually came around to supporting Tillerson before Rubio did.

The difference that I see with Rubio is twofold: He may have actually had the power to stop Tillerson, and he came out with a very strong initial statement.

Here's what Rubio tweeted as Tillerson's name was rising to the top of the secretary of state pile, just before he was officially nominated.

That's a reference, of course, to Tillerson having been awarded the Russian Order of Friendship in 2013. There's even a photo of Tillerson shaking hands with Putin while accepting the award. This fact epitomized the initial wariness among Republicans to support him.

The tweet above is much bigger than Rubio merely saying he has reservations. In a lot of ways, it's a tweet you may have expected from a Democrat who already had decided to oppose Tillerson. It sounded like Rubio drawing a line in the sand before Trump even made the pick.

And Trump crossed it, leaving Rubio in the conspicuous position of deciding whether to buck his own president. Complicating that decision was the fact that Rubio's vote could have proven pivotal, given that he sits on the Senate Foreign Relations Committee, a panel that Tillerson must clear first. If Rubio voted against Tillerson and every Democrat followed suit, Tillerson wouldn't have made it out of committee.

This would have sent an extraordinary message and would have constituted a nearly unprecedented revolt when it comes to a president's Cabinet picks. Back when Tillerson was selected, I did some digging and found that it was basically unheard of for a president whose party had a Senate majority to have his Cabinet picks turned down. When it did happen, it was almost always because of a scandal.

Against that backdrop and given how bold a political move it would have been for Rubio, it seemed unlikely that he would ever really go there. So why come out so strongly in the first place — before the pick is even made — if you know you'll probably wind up voting in favor? (And if Rubio didn't recognize that he would probably vote for Tillerson, perhaps he should have.) To me, it risks looking a lot like Trump called his bluff.

I asked a couple of Rubio allies, and they assured me that it was a principled decision.

“He told me when Tillerson was nominated in December that was going to keep a very open mind and do due diligence before making any decisions,” former Rubio spokesman Alex Conant said, adding: “I don't know how the politics of this play out, and, frankly, I don't think they factored into his thinking one way or the other.”

Rubio friend and GOP consultant Ana Navarro said Rubio was “genuinely troubled” by Tillerson's positions but acknowledged that the politics of it were very difficult.

“Not voting for Tillerson would have been a huge risk with significant political consequences,” Navarro said. “He would have gone against his party's newly sworn-in president, who happened to have won Florida 'bigly,' and he would have gone against GOP Senate leadership and also angered many donors. It would have been walking through a political minefield blindfolded.”

In the end, perhaps we can chalk this one up to the GOP's continued uncertainty when it comes to dealing with the unprecedented president that is Trump. They may be tempted to pick principled fights on given issues, but Trump is not a guy who backs down.

And given that, they better make sure they choose wisely.