As always, you should NOT gauge your analysis of the likely impact of the debate by your own reaction. The only thing that matters electorally is what swing voters are likely to think. And if you're reading this, you're almost certainly NOT a typical voter, and even less are you likely to be a typical swing voter. In fact, you're probably not a swing voter at all. I bet your mind is made up, and there's almost nothing either candidate could plausibly say that would change it, short of fundamental alteration in their entire platform. That's OK! I'm like that myself. But it makes our intuitive reactions an unreliable gauge of electoral impact.
That said, I agree with most other commentators and think Harris had a better debate than Trump. She came off as disciplined and focused. Trump had lots of digressions and elements of weirdness that only his committed base voters are likely to understand and follow. I think, also, Harris successfully baited Trump several times, taking advantage of his poor self-control.
It probably won't have much impact, as swing voters also don't know these things. But Trump demonstrated remarkable ignorance at several points. Most notably, he clearly doesn't know the difference between a bill and an executive order (he said repeatedly that Biden could "sign a bill" about the border, without Congress). It's understandable if lesser-educated voters don't know this. But it's remarkable that Trump doesn't, given that he was President of the United States for FOUR YEARS. Sometimes Trump just deliberately lies for advantage. Here, there was no benefit to calling it a bill rather than an order. He just doesn't know the difference.
I expect this debate will probably have only a small political impact, no more than 1-2 percent. But every little bit matters in a close election.
I have zero sympathy for Trump's whining about the fact-checkers. Yes, they were a bit tougher on him than on Harris. But he also lied a lot more. It's not that she's a paragon of truth-telling; far from it. But she lies "only" about as often as the average politician. Trump does it a lot more than that.
The best news for Harris tonight might have been Taylor Swift's endorsement. Swift is the most popular celebrity in the nation. Probably only a very small fraction of voters will shift as a result. But, again, every little bit potentially matters when things are very close. Should logical, well-informed voters be guided by Swift's endorsement? Obviously not. There's no reason to think she has any useful insight on public policy; though I bet, unlike Trump, she does know the difference between an executive order and a bill! But ignorant voters use crude information shortcuts, and celebrity endorsements are among them.
Harris was very obviously vastly more effective than Biden was on June 27. It's not that she's a great amazing orator. But she's able to convey at least minimal clarity and competence, thereby shifting attention to Trump's flaws. This is a further nail in the coffin of Biden's die-hard defenders who said he should stay in the race. And I say that even though I'm far from a big Harris fan, and she is not who I would have chosen for the nomination, if it were up to me. I'm only going to vote for her because she's a lesser evil relative to Trump (sadly, a very low bar).
Fellow Russian immigrants (most of this group are Republicans, but also pro-Ukraine) and others who care, take note: Trump wasn't willing to say he wants Ukraine to defeat Russia, even though it would have been politically advantageous to do so. It's even more obvious than before that he will sell out Ukraine if he gets the chance. This is one of the biggest reasons why I regard Harris as a lesser evil (along with immigration, trade, integrity of democratic institutions, and maintaining the Western alliance).
While the lesser evil improved her position relative to the greater tonight, it still sucks these are the options before us. In a nation of 330 million people, we should be able to do better. The thought of it almost makes me want to eat a cat!
Despite nativist lies to the contrary, Haitian immigrants don't eat cats any more often than the rest of us. OK, despite the temptation, I probably won't actually eat a cat... probably.