Section 1325! Section 1325! For a few crucial minutes in the middle of the first Democratic presidential debate, Julián Castro (polling average: 0.8 percent) took over the proceedings by challenging his fellow candidates to endorse the repeal of Section 1325 of the Immigration and Naturalization Act.

What’s it about? Don’t ask.

He yelled at Beto O’Rourke about it and expressed his deep disappointment that O’Rourke wasn’t joining him in supporting the repeal of Section 1325.

O’Rourke is at 3.3 percent in the Real Clear Politics polling average, so you can see why Castro thought it was so important to nail him. If he really cuts into Beto’s support, Castro might rise to a whole 1.5 percent.

Meanwhile, Elizabeth Warren — poll average 12.8 percent — could barely get a word in edgewise.

Later, Tulsi Gabbard (0.8 percent) got into a kerfuffle with Tim Ryan (0.6 percent) on whether we should even have gone into Afghanistan in the first place. Gabbard, who seemed to be bidding for the goth vote with her dramatic shock of gray hair, said the Taliban didn’t attack us, al Qaeda did. Ryan’s expression was like Mugatu in “Zoolander” asking if he’d been taking crazy pills.

Meanwhile, Warren — remember, with a poll average of 12.8 percent — still wasn’t getting a word in edgewise.

Bill de Blasio (poll average: 0.4 percent) argued that Americans who support a tough line on immigration had basically been brainwashed by corporations to give corporations a pass. His condescension aside, the mayor was expressing a consensus view on the stage that our immigration policies at the border are evil and that the evil emanates from the White House.

They weren’t just immigration doves. They were immigration antinomians, who disapprove of the enforcement of the laws passed laboriously through our democratic process. At one point, the mostly silent Warren declared that we “must make this Congress reflect the will of the people” — as though it can’t possibly have been doing so because the policies it enacted or refused to enact did not comport with her views.

All in all, Democrats spent far more time talking about how they would help illegal immigrants than about how they would help the voters they most need to win over — the white working-class Obama voters who pulled the lever for Trump in 2016.

Only Tim Ryan, a congressman from Ohio, centered his efforts through the night on the “forgotten” American in the white working class, and he didn’t do a very good job of it.

If I were Brad Parscale, Donald Trump’s campaign manager, I would be dancing a jig — because if this is the way the Democrats and the media want to discuss the economy and immigration, he is going to have a field day with the quotes they will generate from now until the election.

Some random observations: O’Rourke really needed a shave. While delivering an answer in which she inadvertently mentioned she had voted for the first piece of legislation Donald Trump had passed, Amy Klobuchar began to rush and speak in a monotone that made her sound as incomprehensible as Charlie Brown’s teacher.

I kind of liked what John Delaney was saying on health care, so I’m going to assume he is wildly out of step with the Democratic electorate and will have to drop out soon.

Jay Inslee had a good haircut.

Cory Booker did OK most of the night, except for when he broke out in Spanish and reminded us of El Bloom­bito — the Twitter feed by Staten Island wag Rachel Figueroa that made such hilarious fun of Michael Bloomberg’s dreadful Español.

And Warren is still waiting to speak. That’s probably for the best, since her most substantive point was to suggest we needed to do a lot of research and gather loads of data on gun violence in order to solve it. Not a great moment.

The thing is, by seeming to speak hardly at all, she won the night.