In fairness, the “old and frail” part is merely implied. But it’s strongly implied.

I’d place odds that he’s openly referring to her as “Grandma” by next summer at 50/50.

In a POLITICO interview, the 51-year-old senator talked unblinkingly about the possibility of a run, and sought to draw a sharp contrast between himself and Hillary Clinton — none too subtly raising the issue of her age. At 67, she is 16 years older than he is.

“I think all the polls show if she does run, she’ll win the Democrat nomination,” he said. “But I don’t think it’s for certain. It’s a very taxing undertaking to go through. It’s a rigorous physical ordeal, I think, to be able to campaign for the presidency.”

There’s an obvious retort here if you’re a Clintonite looking to smack Rand back, and I don’t mean Reagan’s classic quip about refusing to hold his opponent’s youth and inexperience against him (although that would work fine too). Let’s see if you’re smarter than a witless Hillary apparatchik. Here’s what Team Clinton said; what should they have said?

Adrienne Elrod, the communications director for Correct the Record, a research group backing Clinton, said, “It’s pretty funny that Rand Paul is lecturing on the ‘rigors’ of a presidential campaign, given that last I checked, he’s never been a presidential candidate, or even a candidate for re-election to any office.”

The “excitement and enthusiasm” for Clinton on the campaign trail, Elrod said, “will be far more than Rand Paul can handle.”

The obvious retort, of course, is that Hillary’s several years younger than — ta da — Ron Paul was during his 2008 campaign and will be fully eight years younger on election day 2016 than Paul was by the end of his 2012 campaign. So at a minimum, they can call Rand a hypocrite by noting that he wasn’t concerned about the rigors of the campaign trail for his own flesh and blood. If they want to go further and really make their response sting, they could do what they’re going to be busy doing every day two years from now and spin Rand’s comment as thinly veiled sexism. Rand obviously had no problem with Reagan running in 1980; he had no problem with the even older Ron Paul running twice. If he’s pretend-worried about Hillary’s stamina, is it because she’s older or because she’s a woman? And once you make that move, you can remind the public of Hillary’s one and only apparent accomplishment as Secretary of State: She logged a lot of miles in the air, so clearly she’s used to traveling and gladhanding people. Sounds like presidential material to me.

Honestly, I don’t get the age attacks on her unless Rand’s heard something about her health through the grapevine and is cunningly planting a seed of doubt in the public’s mind which he knows/hopes will flower later when the truth comes out. If he’s right that she’s too old to handle the rigors of the presidency, that’ll become obvious as she scales back public appearances during the campaign. If she doesn’t scale back, then the age attack will either mean nothing on election day or it’ll actually annoy some older voters. And as I say, there’s some “war on women” messaging potential if her health becomes more of an issue than it was for, say, John McCain. The main value in pointing out her age, I think, is in the supremely fun conservative trolling opportunities it affords. If Rand wants in on that, okay, I guess, but I can’t believe he thinks this line of attack is a winner.