The special election in Pennsylvania’s 18th Congressional District isn’t even fully over, but the results are clear: Yet another special election has swung sharply toward the Democrats.

With most precincts reporting, the Democrat, Conor Lamb, clings to a narrow lead over Republican Rick Saccone. Whichever candidate ultimately wins is not the big question. The current district will essentially disappear anyway, because the Pennsylvania Supreme Court has ordered that new congressional districts be drawn before November 2018. Perhaps the winner gets some benefit from running as an incumbent, but that’s not clear, either.

What is clear: The margin between Lamb and Saccone is about 20 points more favorable to Lamb than the 2016 presidential election results in this district. Donald Trump beat Hillary Clinton by 20 points. Lamb and Saccone are essentially tied. This 20-point swing is larger than the average 13-point swing toward the Democrats in the 90 special elections in 2017-2018. (See the Daily Kos special elections tracker for these data.)

Here’s a graph showing the pro-Democratic shift:

All told, Democrats have beat their 2016 presidential margin in 70 percent of these special elections.

If Rick Saccone pulls out a narrow victory, that is cold comfort for the GOP. And high-ranking party officials know it:

The question now is if the Pennsylvania special election will kick off a fresh round of GOP retirements. Clearly it should further energize the funders and voters backing Democratic congressional candidates.