So, after immense anticipation and much back-and-forth argument over the standards for judging the candidates' performance, the winner of the first presidential debate of the general election was not -- well, debatable. Hillary Clinton exceeded the very high bar the news media set for her and won on style (smooth versus incoherent), on substance (on stop-and-frisk, on ISIS, on birtherism, on tax returns, on tax policy, on NATO, on Trump's business record), on endurance, and on visuals. It's hard to find a topic on which Trump scored a clean point.
He did nothing to help himself. The topics didn't favor him -- little on the economy (other than trade), and virtually nothing on immigration -- but he didn't steer the discussion in a more advantageous direction. He gave Clinton a pass on potentially damaging allegations involving her Wall Street ties and the financing of her campaigns.
The big question is how much an effect this will all have on the state of the race. The butt-kicking Clinton administered to Trump ought to move some votes. CNN's snap poll of debate-watchers (which skew about ten points more Democratic than representative samples of voters) showed Clinton "winning" by a 62 to 27 margin. That's actually not as impressive a showing as Mitt Romney after the first debate in 2012, when CNN showed the Republican "winning" by a 67 to 25 margin. Romney did pick up some points in the polls.
At the time though, Romney was not remotely as well-known as Clinton is today, and a similar performance might not pay off as abundantly for her in the two- and four-candidate polls that are conducted immediately afterward, that we should begin seeing late this week. That outcome -- depressing as it might be to her supporters -- would be evidence that the degree of partisan and ideological polarization in this electorate is so powerful that debates, and perhaps even other forms of persuasion like campaign ads, just don't matter this year.
If Clinton does not make significant gains, we will have strong evidence that the best remaining strategy for her campaign is to focus on base mobilization -- making sure her supporters get to the polls. That would be bad news for Clinton, but not devastating, because she has an advantage in the field operations and voter-targeting that are essential to getting out her vote.
There is also a weird dynamic at play with younger voters that might be hurting her, especially after tonight: Many left-leaning millennials seem to think Clinton's already wrapped up the presidency, and are planning not to vote, or to cast a ballot for Gary Johnson or Jill Stein. Media gabbing about Clinton's big win at Hofstra won't exactly galvanize such voters to make a stand for HRC.
As for Trump, he obviously needs to raise his game, and deal forcefully with a potential morale problem among his supporters. What he should pray for is that polarization is so powerful that he cannot possibly lose this race in 90 minutes.