Right out of the box, Rick Perry — under assault for the absurd declaration in his book that Social Security is unconstitutional — used his best reassuring tone to offer “a slam dunk guarantee” to seniors that the program would be there for them. Mitt Romney was positively eloquent in defending Social Security, sounding more like a New Dealer than the Tea Party character he was trying to be for most of the night.

Here’s what’s madding: These days, Republicans can’t stop talking about slashing federal spending so they can keep taxes low. But it’s inconvenient for them that senior citizens are now the strongest Republican group in the electorate and the most conservative group in the country. They play a huge role in deciding Republican primaries. So they get a pass. Better, these conservatives seem to think, to cut student loans or food stamps. Most of the folks who get them don’t vote Republican anyway. Yes, Republicans talk about cutting Medicare, but again, most of the tougher cuts are down the road so today’s senior Republican voters don’t have to be alarmed.

   It was striking that when Perry talked about his idea to “allow all these young people to get out of Social Security,” the CNN camera cut to an older Tea Party member who was smiling and applauding. The applause was for a policy that wouldn’t affect him. It’s easy to clap.

    I am strongly for Social Security, and I, too, would give a “slam dunk” guarantee to today’s seniors. But I don’t pretend to be a small-government conservative, and I would raise taxes to protect programs that I think matter. I’d also make sure that younger American got a fair shake out of the retirement program. These guys pretend to be for small government except when it is politically inconvenient — Ron Paul being the exception, of course. The one true libertarian in the race, Paul would cut just about everything. At least he’s consistent.

   Once again, the consensus on this debate seems right, well captured by Chris Cillizza and nicely illustrated by Dana Milbank: Perry was the loser, Romney won again, and Michele Bachmann was back in the picture. I was also struck by how badly Jon Huntsman did. For one thing, there is something troubling about a guy who was working for President Obama at the time of the health-care fight to turn around and join the crowd by calling it “Obamacare.” It was the sort of shape-shifting he accuses Romney of, and it was just plain ungracious. And to accuse Rick Perry of making a “treasonous comment” on border security was simply ridiculous. Huntsman will never out-Perry Perry, and he demeans himself by trying.

More on the GOP debate from PostOpinions

Milbank: Rick Perry gets exposed

Rubin: Romney, Perry — or someone else?

Bernstein: GOP spins further from reality

Thiessen: A pathetic national security debate

Petri: Rick Perry’s sinister vaccines