A few quick post debate observations without a ton of editing:
1. Everyone will properly make a massive deal out of Donald Trump's virtually historically unprecedented refusal to say that he will accept the results of the election—even after moderator Chris Wallace provided a sorely needed civics election. No, Trump fans, no one was asking him to forego his right to challenge results, as Al Gore did in 2000, in the event that the election is decided by a razor thin margin. But no candidate in modern history refused to accept the results BEFOREHAND. There is a legal process. In the event of a close election, either candidate can avail him or herself of that process, provided that he/she accepts the outcome at the end.
Gore and Richard Nixon before him might well have believed privately that the opposition stole elections, but both avoided calling the legitimacy of the system into question. Ask yourself this: if Trump faced the same situation than Gore faced in 2000, would he concede after the final Supreme Court ruling?
The peaceful transition of power, dating back to 1800, when much apprehension existed as to whether it would occur, is a hallmark of American democracy. It's why we're not a banana republic. It's what made the U.S so unique in 1800.
This comment might've been Trump's single most dangerous and destructive remark in a campaign full of them. He egged on his supporters who are already reticent to trust basic facts, because of beliefs about media bias, and thrust the very fundamental process at the core of our republic into unnecessary and foreboding doubt. Trump demonstrated a contempt for the American system unimaginable from any American politician.
We've had candidates win the popular vote and lose the electoral college (Gore and Samuel Tilden), we've had a candidate receive the most electoral and popular votes (though some historians dispute the popular vote totals), but lose in the House of Representatives (Andrew Jackson in 1824), we've had election results decided after months of drama (1800 and 1876), but the hallmark of our system is a peaceful transfer of power.
Trump failed on the most basic metric by which we can judge any candidate. No doubt this answer is also a disaster for down ballot Republicans who will need to spend the next few days cleaning up after Trump.
2. All of that aside, I still think Trump hurt himself most with his nasty, biting asides, constant interruptions (at one point he wouldn't even let moderator Chris Wallace finish a question without 4-5 interruptions). As I wrote in the Philadelphia Inquirer before the first debate, voters want a likable and relatable candidate. A candidate who interjects that his opponent is a "nasty woman" in the middle of one of her answers is anything but.
According to one tally, Trump interrupted Clinton 37 times, whereas she interrupted him a mere 9 times. Trump also interrupted Wallace 25 times. These antics make Trump appear juvenile, petulant, and the antithesis of presidential. I can't help but wonder how many parents out there watched his performance and thought gee, I wouldn't tolerate that sort of rudeness from my kids, let alone my president.
3. Overall, I think Trump had his best debate in terms of rallying his base, and providing them with exactly what they care about hearing. He flogged Clinton's various scandals, made reference to a new video from conservative provocateur James O'Keefe that raises further allegations of Democratic voter fraud and shenanigans, and he called out several of Clinton's weakest moments. He also showed a slightly better grasp of policy than he had in the first two debates (though the bar was exceedingly low—as the Washington Post's Paul Kane tweeted, many other Republicans could have provided a better performance).
He channeled the anger felt by many conservatives, and repeatedly raised the issue of double standards, whereby conservatives get judged by a harsher standard than liberals, something that has long rankled many conservatives and Republicans, and which resonates deeply with the consumers of conservative media.
4. Moderator Chris Wallace was the biggest winner for the night. He performed well under a glaring spotlight, doing an almost impossible job with aplomb. He won accolades from the left, right and journalists. Yet, as Politico's Hadas Gold savvily pointed out, Wallace employed conservative frames for issues, and a conservative vernacular/language that distinguished his moderation from predecessors.
To provide one example of Wallace's utilization of a conservative frame, he seemed to accept uncritically a disputed AP report purportedly showing that Clinton Foundation donors received special access to then Secretary of State Clinton at the State Department. He also mentioned the amount of money paid to Clinton for a speech to bankers in a question about contradictions between her public statements and private ones, which seemed unnecessary.
Yet, liberal praise for Wallace in spite of these conservative frames reflects the magnitude of the impressiveness of his performance. He challenged both candidates often, throwing their inconsistencies at them and calling out refusals to answer questions. His questions were tough, but fair. Finally, he tried, though sometimes without success, to cut off attempts to repeat points from the first two debates, in favor of discussing issues avoided previously.
Wallace's style offered a road map for a respected conservative news operation that addresses issues important to conservatives, while reflecting rigorous journalism.
5. Clinton had her best debate performance. She hit a home run in responding to a question about allegations that Trump assaulted 9 different women over the previous decades, she demonstrated policy mastery, she displayed more empathy than usual, and she successfully needled Trump into imploding and taking the bait. For most of the night, she was at the top of her game.
She had two weak moments: first, her response to Wallace's question about the discrepancy between her public statements and the speech to bankers with regard to favoring open borders. Clinton brushed aside the remark, offering a touch of context, before pivoting to decry the Russian hacking that revealed the comment. She could and should have been more assertive.
Later, Clinton clumsily sidestepped the question on pay to play, but as Wallace noted, she never answered it. Her campaign has offered far stronger responses with actual facts, and she should have employed one of them before shifting to the good done by the Clinton Foundation. In both cases, Clinton missed an opportunity to assuage some of the uneasiness that many voters still feel about her.
Her supporters will brush these moments aside, arguing that she deftly moved the discussion to more comfortable terrain. But failing to adequately address this distrust is the last thing preventing Clinton from 100% locking up the election (she's very close). It will also have governance ramifications.
6. It won't get the attention it deserves, but listening to Trump essentially say that he didn't care what American intelligence agencies said about who hacked the DNC and Clinton Campaign Chair John Podesta will surely have tongues wagging and jaws dropping in foreign policy/defense/intelligence circles. It demonstrated his unwillingness to accept facts when they don't suit his purposes. This answer also likely hurt Trump with voters—both for its denial of fact, and it's curt dismissal of the intelligence agencies.
7. According to a chart tweeted around, the moderators across the 3 debates failed to ask questions about many key policy issues (like climate change, education, campaign finance, LGBTQ, etc). Moderators confront a nearly impossible task, but perhaps we need more or longer debates if they can't get to so many pertinent and important issues.