A smaller majority, minus the intraparty feuding, could benefit Democrats in two ways: first, it could enable them to devise cleaner pieces of legislation, without blatantly trading pork for votes as they did with the deals that helped sour the public on the health care bill. (As a corollary, the narrative of “Democratic infighting” would also diminish.)

Second, in the Senate, having a majority of 52 rather than 59 or 60 would force Democrats to confront the Republicans’ incessant misuse of the filibuster to require that any piece of legislation garner a minimum of 60 votes to become law. Since President Obama’s election, more than 420 bills have cleared the House but have sat dormant in the Senate. It’s easy to forget that George W. Bush passed his controversial 2003 tax cut legislation with only 50 votes, plus Vice President Dick Cheney’s. Eternal gridlock is not inevitable unless Democrats allow it to be.

Republicans have become obsessed with ideological purity, and as a consequence they will likely squander a few winnable races in places like Delaware. But Democrats aren’t ideological enough. Their conservative contingent has so blurred what it means to be a Democrat that the party itself can barely find its way.