Is Kamala Harris’s surge beginning to ebb? That’s the question raised by the recent New York Times/Siena College poll, which finds Donald J. Trump narrowly ahead of Ms. Harris among likely voters nationwide. Nate Cohn, who covers American politics, explains why some of Ms. Harris’s strengths from just a few weeks ago are now becoming her weaknesses, and the opening that’s creating for the former president. Guest: Nate Cohn, who covers American politics, explains why some of Ms. Harris’s strengths from just a few weeks ago are now becoming her weaknesses, and the opening that’s creating for the former president.