As a rule, most U.S. House incumbents win their re-election bids. The number of congressional incumbents who lose primary campaigns is, in general, vanishingly small.

But this has been a weird year. Roll Call reported overnight:

Embattled Florida Republican Rep. Ross Spano lost his primary Tuesday night, becoming the latest lawmaker to be rejected by his party in a cycle that has been unusually treacherous for incumbents. Navy veteran Scott Franklin was leading Spano 51 percent to 49 percent in the 15th District when The Associated Press called the race just after 9:30 p.m. Eastern time.

Though congressional incumbents who face credible primary rivals tend to face ideological troubles, Spano’s problem was driven by a scandal: he’s currently facing a federal criminal investigation over alleged campaign finance violations.

Spano has already admitted that the transgressions occurred, though he’s argued that the missteps were accidental.

And for some Republicans, including Rep. Matt Gaetz (R-Fla.), the controversy created an electoral challenge that was untenable: Spano’s scandal would make the district more competitive in the fall, which in turn would make matters that much more difficult for the House GOP’s 2020 efforts.

For his intra-party critics, that meant it was time for Spano to go, and looking at the results, it appears just enough Republican primary voters in the district came to the same conclusion.

But stepping back, what’s especially notable is just how many other House incumbents have met the same fate. As things stand, eight sitting representatives have lost in 2020 primaries: William Lacy Clay (D-Mo.), Eliot Engel (D-N.Y.), Steve King (R-Iowa), Dan Lipinski (D-Ill.), Denver Riggleman (R-Va.), Scott Tipton (R-Colo.), and Steve Watkins (R-Kan.).

If that sounds like a lot, it’s not your imagination. In fact, a Washington Post report noted that this is “the highest number of defeats in a non-redistricting year since 1974.”

What’s “a non-redistricting year”? After a census, states often have to reshuffle district lines, and occasionally, two incumbent House members have to face one another when new lines overlap with old ones. It leads to several modern instances in which sitting representatives lose in primaries to other sitting representatives.

But what we’re seeing this year is qualitatively different: the first election cycle since the immediate aftermath of Watergate in which eight House incumbents lost in primaries, not to other members, but to actual intra-party challengers. Tumultuous times, indeed.