The Democrats themselves are saying the reason they lost was due to a lack of enthusiasm for their side, which in turn comes from not getting their infrastructure and BBB plans passed.
It makes sense. If they could get a "progressive" version of BBB passed, they would get more enthusiasm from progressives. If they could get a "moderate" version of BBB passed , they would get more enthusiasm from moderates. They can't have both obviously, but either might have been enough to win in VA. But they passed nothing and they got neither.
Logically their explanation makes sense, but you won't find evidence for it in exit polling because those voters didn't even show up.
The thing I don't like about the explanation is that what's happening at the federal level doesn't reflect on the local and state level stuff, at least in my opinion it should not. But most voters don't think like that, they mostly think about federal level stuff even for local races.

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