CNN  — 

Just one week after the Census Bureau announced which states would be gaining and losing congressional seats before the 2022 election, the dominoes are beginning to fall – and the news is not good for Democrats desperately clinging to their single-digit majority in the House of Representatives.

The big blow came last Friday, when Illinois Rep. Cheri Bustos, one of just seven Democrats who currently represents a district former President Donald Trump won in 2020, announced she would not run again. While Bustos didn’t mention redistricting – and the news that Illinois’ delegation will be forced to shrink by a seat before 2022 – it’s hard not see that, plus the fact that there was no obvious statewide office for her to run for, as contributing to her decision to step aside.

While Democrats control the line-drawing process in Illinois, it will be tough to draw a Democratic-friendly district in the western Illinois area that Bustos’ 17th district covers. (Trump won the 17th in 2020 and 2016.) Which could cost the party a seat that Democrats can ill afford to lose.

And while the Bustos retirement was the headline news out of the 2022 campaign over the last few days, Florida Rep. Charlie Crist’s (D) decision to, again, run for governor – which he announced on Tuesday – creates another problem for House Democrats.

Crist’s 13th district on the western coast of the Sunshine State favors Democrats, yes, but not by wide margins. Joe Biden won the seat by 4 points in 2020 and Hillary Clinton won the seat by 3 points in 29016. But Republicans are in full control of the re-mapping of Florida over the next year, and Crist’s seat could well be a major target now that it is open.

And Crist isn’t the only Florida Democrat looking at statewide office. Rep. Stephanie Murphy (D) has said she is considering a run against Sen. Marco Rubio (R) in 2022. And Rep. Val Demings (D) is considering gubernatorial and Senate bids.

A trio of Democratic open seats in Florida would be a massive gift to Republican redistricters looking to improve on the party’s current 16-11 majority over Democrats – and with a new seat coming to the state after reapportionment.

Another state to keep an eye on is Pennsylvania, where the state’s open Senate seat – Pat Toomey (R) is retiring – is attracting interest from a number of House Democrats, most notably Rep. Conor Lamb who represents a western Pennsylvania seat that Biden won in 2020 but Trump carried in 2016. If Lamb runs, his 17th district could be carved up by the state’s line-drawers – control of redistricting is split between the two parties – who will have to find a way to reduce the congressional delegation by a seat in 2022.

The Senate candidacy of Rep. Tim Ryan in Ohio and the possible Senate candidacy of Rep. Ron Kind in Wisconsin are two other major concerns for Democrats, as both states lost a seat in reapportionment and redistricters will be on the hunt for districts they can compress or eliminate altogether.

Much of this is par for the course in the first election after the decennial redistricting process – especially in states slated to lose a seat (or more) or where the opposition party controls all levers of the line-drawing process.

But every retirement matters that much more to Democrats this election cycle, because their majority is so remarkably thin. At the moment, Democrats control 218 seats to 212 for Republicans, although that margin is expected to grow by a seat next week when Louisiana Rep.-elect Troy Carter (D) is formally sworn in.

Then there’s the ominous cloud of history for Democrats to contend with. According to Gallup, the average numbers of seats lost for a president’s party in a midterm election since 1946 is 25. Since World War II, the average seat loss is 23 for a president’s party in their first term.

Combine it all and Democrats were going to have a hard time holding their majority under the best of circumstances. When you factor in the weight of history and their recent series of problematic retirements (with more likely to come!), the majority looks very, very imperiled.