Who won the debate last night? It's not a basketball game, people; there doesn't need to be just one winner. Hillary Clinton "won" by looking like the nominee (if it weren't so short, her closing statement could've passed for an acceptance speech) and by letting the press replace its overblown "Hillary is struggling" narrative with an overblown "Hillary is back!" narrative. Bernie Sanders "won" by reaching new fans (an awful lot of people Googled his name last night) and by establishing himself as the main alternative to Clinton. I won't be surprised if in the next poll, Clinton and Sanders both gain at Joe Biden's expense.
Too much of the post-debate commentary has focused on Sanders' refusal to go after Clinton for her email scandal, declaring that he's "sick and tired of hearing about your damn emails." It was a memorable moment, but it's hard to see how it changes the picture: He hadn't been attacking her for the scandal before, and it isn't the sort of issue he was ever likely to jump on. If Clinton's emails injure her candidacy in the primaries, it's going to be because (a) she lands in serious legal trouble and/or (b) party leaders are so worried that the issue will hurt her in the general election that they switch their loyalties to Biden. Neither of those is contingent on anything Bernie Sanders says.
So Clinton and Sanders are both gaining steam, with Clinton, as always, the likely nominee; Biden is still in the wings, but he's somewhat less likely to jump in; and a few other candidates are hanging around without much support. (As I wrote last night, Webb may get a small bump just by showing any rural populist Democrats who tuned in that he exists. But not a bump big enough to have an impact on the outcome.) This debate may have changed the race a little, but mostly it clarified where everyone already was.