Biden flexed his dexterity at the State of the Union

Republicans are quick to suggest that President Joe Biden has lost a step — but he proved nimble enough Tuesday night to box them in on Social Security and Medicare. And he did it, in part, by going off script.

Nearly halfway through his State of the Union address, Biden said that "some Republicans want Medicare and Social Security to sunset every five years" and that others would like to use the possibility of defaulting on federal debt as leverage to cut those programs.

Republicans jeered. Rep. Marjorie Taylor Greene, R-Ga., a newly empowered voice in her party, yelled, "Liar!"

At first, Biden offered to provide documentation. Then, he simply accepted the response as on-the-spot agreement from the GOP to keep the programs intact.

"As we all apparently agree," he said, departing from his prepared remarks and grinning like a cat with a canary feather stuck in his teeth, "Social Security and Medicare is off the books now."

There's a duality to what sounded like a snap policy victory for Biden: To whatever extent he protected the entitlement programs, he also made it harder to campaign on the idea that Republicans are bent on destroying them. But perhaps more important, as he gears up to run for re-election, Biden demonstrated the mental dexterity that critics — and, in private moments, even some allies — say he lacks.

If anything, Biden seemed sharper without the script.

"It was a great Biden moment and showed why he needs to be given more opportunities to freewheel and talk from his gut," said Faiz Shakir, who ran Sen. Bernie Sanders' 2020 primary campaign against Biden. "He basically conducted a real-time pledge-a-thon and got vast majorities to commit to taking Social Security and Medicare off the negotiation table."

It’s not hard to conclude that Biden won one of the clearest victories of any president addressing hecklers in a speech before Congress. It's similarly easy to figure that most people won't be thinking about the 2023 State of the Union when they vote in 2024.

But the themes of the exchange may help frame the coming months and the next election.

Biden wasn't lying when he said there was some support in the GOP for letting Social Security and Medicare expire after five years if Congress doesn’t pass a new law. Sen. Rick Scott, R-Fla., then the chairman of the Senate GOP's campaign committee, proposed just such a plan during the midterm elections. Even though other Republican leaders distanced themselves from Scott's agenda, it became an issue in some races.

But his argument about the debt limit was on shakier ground. Republicans were quick to point out Tuesday night that House Speaker Kevin McCarthy, R-Calif., has said that "cuts to Medicare and Social Security" are "off the table."

Either way, Biden may have handed the GOP an unexpected gift by claiming a policy victory on the entitlement programs.

"President Biden gave up his political cudgel by providing Speaker McCarthy and every other Republican a chance to publicly stand in support of Social Security, and they happily took the opportunity," Republican strategist Matt Mowers said.

For Democrats, there was a certain pleasure in seeing Biden dance around the ring.

"Did @potus just bait-and-switch the GOP into agreeing to protect Medicare and Social Security on live national TV?!" former Rep. Tom Perriello, D-Va., wrote on Twitter.

That's exactly what he did.

This article was originally published on NBCNews.com