The GOP Senate race in Missouri is causing Republicans the most consternation of any primary this cycle, given the possibility that embattled former Gov. Eric Greitens — who resigned amid scandal and now faces allegations of abuse from his ex-wife — could torpedo their chances in what should be an easy hold.

There's been a lot of movement in the contest to succeed retiring Sen. Roy Blunt over the past few weeks, even as Greitens has remained defiant. But two primary challengers — to the relief of the national party and many Missouri Republicans — do appear to be catching him in polling.

But the most intriguing development this week is that Democrats landed a major candidate with the last-minute entrance of Trudy Busch Valentine, heiress to the beer fortune founded by her father, Anheuser "Gussie" Busch. She's a self-funder who could give Democrats a very credible and appealing candidate if Greitens is the nominee, adding further worry for national and state Republicans. She still faces ten other Democrats on the ballot, including the current frontrunner, Marine

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