Sen. Thad Cochran (R-MS) will resign from the Senate on April 1. Cochran, 80, has been in poor health and was rumored to be considering retirement. “I regret my health has become an ongoing challenge,” Cochran said in a statement. He was first elected to the Senate in 1978 and currently serves as the chairman of the Senate Appropriations Committee. The decision puts the spotlight on Chris McDaniel, a conservative Republican who is trying to unseat Mississippi’s other senator, Roger Wicker.