The second hour of the debate began with conversation about age — and how much it matters.

Moderator Tim Alberta, chief political correspondent for Politico, broached the subject with the three oldest candidates: Sen. Bernie Sanders (D-Vt.), who is 78, and then former vice president Joe Biden, who is 77.

Then he turned to Sen. Elizabeth Warren (D-Mass.), who is 70.

“Senator Warren, you would be the oldest president ever inaugurated,” Alberta said. “I’d like you to weigh in on this as well.”

Warren had an answer at the ready.

“I’d also be the youngest woman ever inaugurated,” she said, grinning.

The crowd erupted in cheers. On Twitter, viewers and analysts commended what seemed, to all, to be the ultimate witty comeback.

Rep. Ayanna Pressley (D-Mass.), who has endorsed Warren for President, tweeted Warren’s quote, with an attribution that suggests her words will go down in history.

Age has been a central issue in the 2020 campaign, as three septuagenarians have consistently led the polls. Of the three, Warren has received the least scrutiny for her age — likely both because she is considerably younger than Biden and Sanders, and because she, by many accounts, “looks young.”

She is known for running through crowds of supporters at campaign events and standing in “selfie lines” for hours. At a recent rally in Rock Hill, S.C., a local councilwoman, Nikita Jackson, commended Warren on her “energy” and “stamina.”

“I was just amazed that when you first came out here, Sen. Warren, that you ran up those steps the way that you did, and all this energy and stamina that you have,” she said.

It appears that’s the energy that Warren is bringing to the debate tonight.

All eyes are on the Kentucky Senate primary. Women there say voting has never felt so urgent.

‘You don’t hear me when I speak, you don’t hear me when I cry, but you’re going to hear me when I vote’

The DNC sent an email promoting 11 Democratic senators that ‘urgently’ need support. Not one was a woman.

It was a ‘mistake,’ the Democratic National Committee said in a statement

The protests could change who Biden picks as VP. Will he choose a black woman?

‘We know black voters are going to make this election. And their level of enthusiasm matters.’