Missouri's other contentious House primary
The Republican primary in the dark-red 3rd District has gotten a fraction of the attention of Bush's contest in the 1st, but it has similarly high ideological stakes. Old-guard Republican Rep. Blaine Luetkemeyer is retiring, and it seems likely he will be replaced by a more hardline conservative, former state Sen. Bob Onder (whom Luetkemeyer also defeated in the 2008 primary en route to winning this seat in the first place). A bunch of GOP heavy hitters (Trump, the House Freedom Fund, the Club for Growth) have lined up behind Onder, who was known for his obstructionist ways in the state legislature.
Not everyone is thrilled about the prospect of Onder heading to Congress, however. Establishment-aligned super PACs have spent $4.9 million opposing Onder or supporting his main opponent, former state Sen. Kurt Schaefer, outdistancing the $3.0 million groups have spent to boost Onder or attack Schaefer. Luetkemeyer is supporting Schaefer as well, but it doesn't seem like he's catching on. Onder's campaign recently released a poll from Remington Research Group showing him leading Schaefer 34 percent to 14 percent, with five minor candidates combining for 16 percent, and 35 percent undecided. Even if we assume that poll is exaggerating Onder's support, it's unlikely that it's off by 20 whole percentage points.
—Nathaniel Rakich, 538