CNN  — 

Nothing in American politics happens in a vacuum.

That includes the surprise retirement announcement by Ohio Republican Sen. Rob Portman on Monday.

Portman’s retirement is rightly understood as simply the latest piece of evidence that being a so-called establishment Republican – or, really – anything but a die-hard Trump Republican – is no fun at all.

“Congress is no place for a sensible Republican anymore,” tweeted Brendan Buck, a former top aide to speakers John Boehner and Paul Ryan, in the wake of the Portman news.

It’s hard to argue against Buck’s point. In October 2020, Pennsylvania Sen. Pat Toomey, who, like Portman, had developed a reputation in the Senate as a pragmatist, announced he wouldn’t run again in 2022. North Carolina Sen. Richard Burr, who is the very picture of country-club Republicanism, is also not running for another term next November.

And that series of retirement decisions follows several years of House Republicans walking away from Washington. As David Wasserman of the Cook Political Report, a handicapping tipsheet, noted way back in July 2020:

“Fact: when President Trump took office in January 2017, there were 241 Republicans in the House. Since then, 115 (48%) have either retired, resigned, been defeated or are retiring in 2020.”

It’s not hard to connect the dots. And just in case you can’t, well, Portman did.

“I don’t think any Senate office has been more successful in getting things done, but honestly, it has gotten harder and harder to break through the partisan gridlock and make progress on substantive policy, and that has contributed to my decision,” he said in his retirement announcement.

Put yourself in Portman’s shoes. He just spent four years under a Republican president with whom he disagreed on, well, a whole lot. And now, if he ran again, he would face the very real possibility of a Trump-backed primary challenge – maybe from Rep. Jim Jordan – that even if he won would have damaged him politically.

And for what? A party that is barely recognizable from the one Portman has served in for much of the past three decades.

The Point: Trump isn’t president anymore. But the way he wrenched the party into a cult of personality – and away from core GOP principles – continues to have major reverberations.