President Trump on Monday was the latest big political star to swing through Mississippi and boost a candidate in a red-state Senate race that suddenly seems competitive.

© Doug Mills/The New York Times

President Trump will stump for a senator in a state he has won three times by double digits, and as Democrats see a path to victory.

© Haiyun Jiang/The New York Times

Farmers and ranchers have supported President Trump for a decade. But the war in Iran, tariffs and other administration policies have soured some on the G.O.P.

Scott Colom, a state prosecutor, is running against Senator Cindy Hyde-Smith, a Republican who denied him a seat on the federal bench. In a tough year for the G.O.P., Democrats see hope for his long-shot bid.

© Rory Doyle for The New York Times