I don’t want to throw cold water on Conor Lamb’s apparent victory tonight, but I do want to point out one little thing: when a congressional seat opens up and there’s no longer an incumbent, that can produce a 10-point swing all by itself. Back when Democrats still ran candidates in the Pennsylvania 18th district, Tim Murphy typically won with about 63 percent of the vote. This means that a non-incumbent Republican could probably expect about 55 percent of the vote—that is, a 10-point victory. A zero-point victory for Conor Lamb is, therefore, roughly a 10-point swing in favor of the Democrats.
Everyone should probably ignore the “20-point swing” nonsense that cable news has been regurgitating endlessly. This is based on Donald Trump’s winning margin in the presidential election, but that’s apples-to-oranges. It’s congressional contests that matter. Besides, a 10-point swing is still pretty good, especially since Democrats got outspent 4-to-1, so there’s no need to exaggerate things. Let’s all stay reality-based here.