Photo: Brian Snyder/Reuters

Kamala Harris faced a difficult task in the first presidential debate. Her training and skills are those of a prosecutor, but her main task was not to be a prosecutor. It was to define herself for an electorate whose deciding bloc still knows too little about her to be sure she is worth supporting.

Harris’s answer to this dilemma was either a brilliant strategy or serendipity. She baited Donald Trump into losing his patience, and then used the visual contrast between them to position herself as not only a plausible president, but the only plausible president on stage.

Harris signaled her intentions early in the debate, when she invited the audience to watch a Trump rally. Here she revealed something that only political obsessives know: The Trump who performs at rallies is a terrifying, disorganized clown whose incoherence is barely captured in the short clips that appear in news coverage.

Harris also did something clever by noting that crowds leave his rallies early because they’re bored. Trump is strangely obsessed with his rally crowds (as Barack Obama noted during his speech at the Democratic National Convention), and by challenging their size, he’s sent into a tailspin.

From that point on, Trump began doing exactly what he did at rallies. He yelled endlessly, cursed and ranted, struggling to stay on topic or define his concepts in a way that non-superfans could follow. He made outlandish, false claims about illegal immigrants eating pets, blamed the January 6 riot on “excessive police,” and repeated his false claim that he had won the 2020 election.

Harris’s engagement on issues was largely, if not always, successful. She couldn’t explain all the issue-position reversals of her 2019 campaign. On several early questions, she resorted to filler words to keep her sentences moving. She forcefully asserted, “You’re not running against Joe Biden, you’re running against me,” but made only a middling attempt to distance herself from a president with a dismal approval rating. (On abortion, she slashed Trump, watching as he dodged questions about whether he would veto a national abortion ban.)

Harris’s most obvious success was in her role as president. She repeatedly touted her economic plan and refuted the charge that she lacked ideas, which is meant to portray her as a lightweight. She also did this by citing her experience in foreign policy, meeting with Volodymyr Zelenskyy and organizing a NATO response to the Russian invasion. The importance of these validators may be overlooked, but many Americans have outdated notions of presidential qualifications, associating them with masculinity.

Most importantly, she positioned herself as president by appearing calm and confident, a stark contrast to the bellowing lunatic on stage next to her.

The Republican response tells the story of the outcome. Conservatives complained about the moderators (who effectively gave Trump ten minutes more time than Harris). Reince Priebus bravely pointed out that Trump’s numbers never change, a defensive response to the implicit fear that his numbers would drop. Trump seemed to acknowledge that he was losing, a realization that may have made him even angrier.

Harris’ debate plan couldn’t have gone much better.