1. Most debates, whatever their other (dubious) merits, are not good vehicles for determining how candidates differ on substantive policy questions. This debate was no different. The policy discussions, when they occurred, often stayed at a superficial level or departed from reality, and the moderators did not consistently follow up when candidates dodged their questions (which both Trump and Harris did repeatedly). The assumption that these events are essential elements of the democratic process continues to be thoroughly unconvincing.
2. Harris is often compared to Barack Obama for obvious reasons, but her debate style is actually much closer to that of Joe Biden (at least, the pre-2024 Biden). She's not really a facts-and-figures memorizer or someone who shows off command of policy detail; she prefers to state more general themes and present her personal biography as an adequate answer to questions about what she would do to solve this or that specific problem. In another context, an opposing candidate would be able to repeatedly push her out of this comfort zone.
3. Luckily for Harris, (a) she's not running against another candidate, and (b) there's nothing the political media appreciates more than strategic cleverness. Harris's transparently intentional attempts to distract and infuriate Trump by talking about people leaving his rallies in boredom or Wharton School economists trashing his economic plan will be widely hailed as a stroke of political genius, ensuring—in combination with Trump's behavior—that the press will declare her the winner by a wide margin. Add "they're eating the dogs" to the mix, and you have the formula for a solidified conventional wisdom that the debate was disastrous for Trump. But we'll see if it actually registers in the polls.
4. We can also expect considerable media coverage of Taylor Swift's post-debate endorsement of Harris. That's surely welcomed by the Harris campaign, and any positive story is valuable in a very close election. But if high-wattage celebrity support actually moved millions of votes, the Democrats would never lose.
5. A very confident Harris campaign immediately challenged Trump to another debate, and Trump may well accept the offer in order to try for a comeback in Round 2. But, really, what's the point of having another one of these?