For the past few years, the 80-year-old's health has come into question, and he missed several weeks of work due to a urinary tract infection in 2017. But Cochran was able to return to the Senate in time to vote on critical GOP legislation, winning praise from President Trump.
In a statement, Cochran said "I regret my health has become an ongoing challenge. I intend to fulfill my responsibilities and commitments to the people of Mississippi and the Senate through the completion of the 2018 appropriations cycle, after which I will formally retire from the U.S. Senate."
Senator Cochran was first elected to his seat in 1978, and has served as chair of the Appropriations Committee since 2015. He reflected on his tenure in his statement on Monday, saying "I've done my best to make decisions in the best interest of our nation, and my beloved state. My top concern has always been my constituents in Mississippi. My hope is by making this announcement now, a smooth transition can be ensured so their voice will continue to be heard in Washington, D.C."
Cochran's resignation means both US Senate seats in Mississippi will be open for the taking in this fall's special election. Junior Senator Roger Wicker is up for reelection, and is facing a primary challenge from Tea Party candidate Chris McDaniel on June 5. McDaniel unsuccessfully challenged Cochran in 2014's primary race.
Mississippi governor Phil Bryant will appoint Cochran's replacement until a permanent officeholder is elected in November. The Washington Post reported on February 2 that Senate Majority Leader Mitch McConnell and President Trump both support a plan for Governor Bryant to appoint himself to the seat, but no sources were cited in the article.
The Clarion Ledger out of Mississippi has reported that Bryant was not interested in Cochran's seat, and said the retirement of Cochran has caused political chaos in the state. While Republicans are favored to retain both US Senate seats, the Ledger said "Democrats' best bet is a two-man showdown with McDaniel."