Wisconsin Assembly Speaker Robin Vos, a Republican long considered a towering figure in the politics of a perennial battleground state, announced on Thursday he would not seek re-election.According to The Associated Press, a health scare he had late last year contributed to the decision.In his speech on the assembly floor, Vos revealed that in November, he suffered a mild heart attack. This was not the principal reason he decided not to seek re-election, he emphasized, but it was “the tap on the shoulder that I needed to make sure that my decision is right.”Vos, who was college roommates with former Republican chairman and White House chief of staff Reince Priebus, has served in the state assembly for over a decade, first helping right-wing Gov. Scott Walker curtail union powers, slash education funding, and roll back voting rights, then serving as a blockade on the ambitions of Democratic Gov. Tony Evers when he took office — all empowered by aggressive Republican gerrymanders that gave him a hammerlock grip on power. He has effectively served as the Wisconsin GOP's leader through much of the 2020s.After Democrats elected a liberal majority to the state Supreme Court, the legislative gerrymanders empowering Vos were overturned, throwing the GOP's power over the legislature into uncertainty as voters head into an election year that polls warn could be a massive backlash against President Donald Trump.