I have good news and bad news for Marco Rubio fans: he received an enthusiastic response in the main hall of the Conservative Political Action Conference (CPAC). The bad news is that is probably where his popularity peaked.

Sure, the audience appreciated Rubio's jokes about being thirsty. Every sip got a laugh. (Will these continue in 2016? It may not be possible for water to go bad, but surely that bottle has passed its sell-by date?) And his ineffable but oft-cited proximity to the last Republican ticket gives weight to the argument that CPAC is still relevant, still a box every GOP hopeful needs to check on their way to the convention.

But institutional legitimacy can cut both ways here: as much as the attendees want to believe that they're helping to shape the GOP's future, they have an ambivalent attitude towards its present.

The idea that Rubio is a rising star is itself a truism. And as he continues to play the scavenger hunt that is the party nomination process (collecting "CPAC speech", "hot-button bipartisan legislation"), it has become increasingly clear that he has become a rising star partly because he does not threaten to dislodge any of the dwindling "red giants" already lodged in the Republican firmament.

Rubio argued explicitly for the old-wine-new-bottled approach to the issue almost every speaker here has dealt with at least tangentially: why aren't we winning? It's been said that the GOP's unpopularity and sound defeat of 2012 will provide an opportunity for necessary soul-searching, but if that's so, count on Rubio to conduct that operation gently, in flattering light.

We don't need a new idea. There is an idea. The idea is called America, and it still works.

So said Rubio, spouting patriotic-sounding nothingness like an old pro. There's nothing wrong with the Republican party, he insisted, it's just misunderstood. Working people "see" the party as "fighting for the people who have made it", and maybe the party isn't even in that much trouble! So it's "foolish" to think there is some kind of division among its members.

That would be news to those in the ballroom venue at CPAC, whose equally enthusiastic reception for Rand Paul – who followed immediately after Rubio – by itself suggests a party in the throes of either an identity crisis or a simple mitosis. Rand was as brashly critical of the GOP as Rubio had been deferential, as casual as Rubio was disciplined. Contrast Rubio's painfully choreographed water schtick to Paul's easy fielding of a friendly heckle:

Don't drone me, bro!

The cheers for Rubio came because these ideas are familiar, even cherished, but they are not going anywhere. You might even say they're "stale and moss-covered", as Paul described the GOP. Paul was savvy in how he proposed to roll that stone, but he didn't necessarily offer his own muscle. Instead, a good chunk of his closing was a flattering portrait of his audience (all politicians can go soft-focus when the moment calls for it) – as distinct from the GOP itself.

You guys, he said, you guys are the smart ones here! In his own words:

"The Facebook generation can detect falseness and hypocrisy from a mile away. I know. I have kids. They are the core of the leave-me-alone-coalition."

Rand Paul is not really a libertarian – just ask any of the actual libertarians here – but he smartly positioned himself as a grown-up who understands that the next generation of voters mostly likely are.

It's amazing how Marco Rubio can be so close to the age of the majority of CPAC attendees, and yet fail to speak to them. Rand Paul is ten years older than Rubio, but speaks fluent Generation Y.

There's no question that the Republican party could benefit from a bilingual candidate, but which languages should he speak?

• This article was updated with an additional quote from Marco Rubio at 7.30am ET on 15 March