One way to look at Monday’s night presidential debate: Both candidates were speaking, time and again, to marginal voters. Specifically, to young Americans, and for a considerable time to young black Americans in particular, people who may or may not choose to vote, may choose to vote for a third- or fourth-party candidate or may (Democrats hope) turn out to vote in large numbers for Hillary Clinton. Clinton’s strategy of replicating the 2012 Obama 51 percent majority requires high turnout among groups that over history have had a low propensity to vote — blacks, Hispanics, young people. Trump’s strategy, given his unpopularity with young voters, is to deter them from voting for Clinton, especially considering that the black and Hispanic percentages among young people eligible to vote is higher than those percentages among older people.

“She’s been doing this for 30 years,” Trump said near the beginning of the debate, while talking about trade. The number’s not quite accurate: Clinton has been a national figure for only — only! — 25 years, since Bill Clinton began running for president in 1991, but she was also, as speakers at the Democratic National Convention mentioned over and over, a public policymaker starting at least when Bill Clinton was first elected governor in 1978, 38 years ago. “And Hillary, I’d just ask you this,” Trump said some minutes later. “You’ve been doing this for 30 years.” There’s no clear antecedent for “this” — Trump was riffing about energy, debt, trade — but the point was made again. He even lapsed into absurdity — “You’ve been fighting ISIS your entire adult life” — which is impossible because the Islamic State didn’t exist for most of that time. Much later in the debate, he chimed in on ISIS. “So she talks about taking them out. She’s been doing it a long time.” And near the end of the debate, he chimed in, “Hillary’s has experience, it’s bad experience.”