Rep. Todd Akin, who played up his tea party credentials and conservative appeal, broke out from a three-way Missouri Republican primary on Tuesday to earn the right to take on Democratic Sen. Claire McCaskill, setting up one of the most closely watched Senate races of 2012.

Akin won a contest defined by which candidate was the most conservative. In doing so, he beat out Sarah Palin's candidate of choice, former state treasurer Sarah Steelman, and John Brunner, a businessman who poured more than $7.5 million of his own money into the race.

In Michigan, meanwhile, Republicans selected former Rep. Pete Hoekstra to oppose Democratic Sen. Debbie Stabenow in November. Democratic Rep. John Conyers staved off a primary challenge in a slightly redrawn district to advance to November's election, when he will be strongly favored to win a 25th consecutive term in Congress. Rep. Gary Peters defeated Rep. Hansen Clarke in a member versus member Democratic primary also brought on by congressional redistricting.