A second factor contributing to the GOP retirements is that the Trump presidency has turned safe Republican suburban districts into battlegrounds…

“The suburbs are diversifying and moderating so rapidly that many of the districts Republicans drew back in 2011 are no longer reliable,” says Wasserman.

In 2018, Democrats ousted two Texas Republicans in Houston and Dallas. “Historically, the cities have been bright blue and surrounded by bright red doughnuts of Republican suburban voters,” Texas senator Ted Cruz told the Washington Post last week. “What happened in 2018 is that those bright red doughnuts went purple — not blue, but purple. We’ve got to do a more effective job of carrying the message to the suburbs.”…

The GOP’s suburban problem isn’t limited to Texas. Retiring Georgia congressman Rob Wooddall won reelection in his district northeast of Atlanta by 21 to 31 percentage points from 2012 to 2016, but he won reelection by just two-tenths of a percentage point in 2018. When a blue wave swept over the House GOP in 2018, Republicans lost districts that include suburban areas in states as red as Kansas, Utah, and South Carolina.