Rep. Todd Akin, who played up his tea party credentials and conservative voting record in Congress, defeated Sarah Steelman - Palin's candidate of choice - and businessman John Brunner, a self-funding candidate who poured more than $7.5 million of his own money into the race, to win Missouri's Republican primary Tuesday.
Akin's prize? A shot at vulnerable Democratic Sen. Claire McCaskill in what will be one of the most-watched Senate races of 2012.
Palin made Steelman her fifth Senate endorsement of 2012 and, before Tuesday, she was four-for-four. The former Alaska governor and vice presidential nominee, who campaigned hard for Steelman, cutting TV and radio ads and appearing at campaign events, added more glitz to a race that always had big national implications. Republicans need to net four seats to take back the Senate in November and the GOP says McCaskill is one of their top targets.
In the end Akin, who touted the endorsement of another prominent Republican, Mike Huckabee, emerged from a competitive, three-way race largely run over who was the most conservative potential opponent for McCaskill. Akin continued to play up his conservative credentials on Tuesday night, even as he switched his focus to McCaskill.
"The choice is clear in November," Akin said in a victory speech. "The big-spending, budget-busting, job-killing liberal or the less-spending, balanced-budget, job-creating conservative."
In an interview with The Associated Press, McCaskill said, "I don't know that Missouri voters will ever have more of a contrast." She added: "The issue here is not whether you can label him a conservative, but whether or not he is on the fringe - a very extreme candidate. I believe he is."
In another Senate primary held Tuesday, Michigan Republicans selected former Rep. Pete Hoekstra to oppose Democratic Sen. Debbie Stabenow in November.
Elections were held in four states Tuesday. They included two member-vs.-member Democratic primaries, as well as a challenge to longtime Democratic Rep. John Conyers of Michigan.
In Missouri, Rep. William Lacy Clay defeated Rep. Russ Carnahan in a showdown of two of Missouri's most prominent Democratic families. In Michigan, Rep. Gary Peters bested Rep. Hansen Clarke. Both primaries were brought on by redrawn congressional districts.
Conyers survived his race, a primary challenge in a slightly redrawn district, to advance to November's election, in which he is strongly favored to win a 25th consecutive term in Congress.
The Missouri Republican primary was the most anticipated result on Tuesday, if only because it finally gives Republicans a standard bearer in their quest to unseat McCaskill.
Polls ahead of Tuesday's primary showed any of the three potential GOP nominees stood a good chance of defeating McCaskill in November. Akin, 65, has a strong conservative voting record in Congress. A former Army officer, engineer and state lawmaker, Akin he first won election to the U.S. House in 2000 after narrowly winning a five-person Republican primary.
In Michigan, Hoekstra enters his race against Stabenow as the underdog. Stabenow, the chairwoman of the Senate's agriculture committee, is seeking a third term and has enjoyed a steady lead in polls.