After months of deliberation, GOP Rep. Fred Upton (MI-06), first elected in 1986, finally announced his retirement. Upton's exit is the fourth of the ten GOP members who voted to impeach Donald Trump last year and averts a member vs. member primary against Rep. Bill Huizenga, who has Trump's endorsement for the newly drawn 4th district. But most significantly, it further thins the ranks of Republican House moderates.

Upton had been encouraged by Democrats, including Rep. Debbie Dingell (MI-12), to run one more time. And just last month, Upton tested the waters by going up with $200,000 in ads defending his bipartisan record and work towards drug breakthroughs.

However, Upton's tightrope-like path to renomination in the August 2 primary got even narrower when hard-right state Rep. Steve Carra dropped out and Trump switched his endorsement to Huizenga, denying Upton the benefit of split pro-Trump opposition. Upton represents 64 percent of the newly drawn 4th CD to Huizenga's 25 percent, but in the end, a one-on-one race against a Trump endorsee was a bridge too far.

Of the six remaining

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