How Donald Trump lost it

Like Taylor Swift, Kamala Harris did her research, plus: A champion debate coach grades the night

When Taylor Swift capped Kamala Harris’ winning night with a full-throated endorsement Tuesday, the megastar posted on Instagram, “I’ve done my research, and I’ve made my choice,” wrote Swift. “Your research is all yours to do, and the choice is yours to make.” She signed her post, “With love and hope, Taylor Swift, Childless Cat Lady,” a dig at Trump’s running mate J.D. Vance.

Kamala Harris did her research too. And it showed.

From forcing former President Donald Trump into a handshake to nailing her closing statement, Harris dominated the debate at Philadelphia’s National Constitution Center.

Harris had clearly taken a deep dive into the world of Donald Trump — and she crafted a series of assertions that seemed surgically designed to prod the former president into damaging his own cause. Throughout the evening, Harris glanced over at Trump to see if her strategy was working, and came away smiling, pleased at the way her goading was stoking his anger.

Trump, who seemed unsure at times wh…