You might think that the special elections so far this cycle are a good sign for O’Rourke. To the degree that they suggest a national environment that leans heavily Democratic, they are.
On the other hand, there’s something worrying about the special elections for O’Rourke as well.
The special elections have followed a similar pattern: the 2012 presidential vote baseline has been far more telling than the 2016 presidential vote baseline. If that holds in Texas, it’s a big problem for O’Rourke. The reason being that Texas was one of the few states where Democrats did better in 2016 than in 2012, even as the nation became more Republican leaning.
What O’Rourke needs to win is for voting patterns to follow 2016, and then receive an additional boost on top of that. That’s certainly plausible. The vote patterns in the 2017 Virginia elections looked a lot more like 2016 than 2012. But even there, Virginia Democratic candidates didn’t do that much better than Clinton did in 2016.