This is a surprise, and indicates that Thad Cochran will seek one more term.
I think Cochran and Lott want to try to tie or break Jim Eastland and John Stennis’s records for service.
The longer Cochran and Lott stay in the Senate, the longer Michael Moore stays out of the public eye and becomes a “has been”. Michael Moore is the only Rodent who could make an open Senate seat in MS a competitive race.
Also, I think Lott and Cochran think their senority helps in getting hurricane relief for their state.