On Monday, Republican Rep. Devin Nunes announced he would resign from Congress at the end of the year in order to become the chief executive officer of former President Donald Trump’s new media company. 

The move is puzzling on the surface, given that the 2022 midterms are shaping up to be a good year for Republicans and Nunes, who was first elected in 2002, was in line to chair the powerful Ways and Means Committee in a GOP-led House. But in other ways, it wasn’t a surprise: Nunes is a close ally of the former president. He earned bipartisan criticism for giving Trump preferential treatment during the House probe into Russian election interference in 2017, and he wrote a memo accusing the FBI of unfairly going after Trump. And it is not unprecedented for a Republican to forgo a top job in Congress in favor of a career in conservative media: House Oversight Committee Chair Jason Chaffetz resigned in 2017 in order to join Fox News.

Nunes’s decision also made sense in light of the draft congressional map released last month by California’s independent redistricting commission. Though these lines are likely to change somewhat before being approved, the draft moved Nunes’s Central Valley district from a FiveThirtyEight partisan lean of R+11 (meaning it was 11 percentage points redder than the nation as a whole) to D+5 (meaning it would be 5 points bluer). Nunes’s options under this map would have been to risk losing reelection in this new light-blue seat, challenge one of his Republican colleagues in an adjacent seat, or run in a Republican-leaning open seat dozens of miles north of his hometown. None of those options was probably very appealing.

However, the fact that Nunes is resigning before the end of the 117th Congress means that there will likely be a special election to fill his seat, and because that election is to serve out the rest of the term Nunes was elected to in 2020, it will take place under the current lines of California’s 22nd Congressional District. California Gov. Gavin Newsom hasn’t yet announced when that would occur, but the conventional wisdom is that the all-party primary will take place in April, with a runoff (if necessary) between the top two finishers in June, coinciding with the state’s regularly scheduled primary election. But despite the likelihood that the 22nd District won’t exist in its current form a year from now, several local politicians have already expressed interest in a campaign.

While Republicans would certainly be favored under the current lines, the final margin in the special election could offer us another clue as to the mood of the country heading into the 2022 midterms. If Republicans win in a landslide, it would be consistent with other recent election results that suggest the 2022 midterms will be a “red wave” election; if Democrats come close (or even win), it might call that narrative into question. Of course, we’ll have to consider that result in the aggregate with any other special elections that take place in 2022 (so far, there’s only one other federal special election on the docket, in Florida’s 20th District), all of which we’ll be covering here at FiveThirtyEight, so stay tuned.