Former Republican senator Larry Pressler will run for the Senate in South Dakota again, this time as an independent, he announced Thursday, officially inserting a new dose of uncertainty into a race that represents the GOP's best pickup opportunity.

"Today, I am announcing that I am running for the United States Senate, and I intend to win," Pressler said, according to the Sioux Falls Argus Leader. Pressler had hinted earlier this year that he was probably going to run.