Republican Rep. Fred Upton of Michigan has ruled out running for U.S. Senate next year.
Upton, of St. Joseph, has held southwestern Michigan's congressional seat for 30 years.
He said Friday there was "a path" to running, but he has chosen "not to follow it."
He instead will seek re-election to the House, saying "we need focus and fortitude in Washington now more than ever."
Third-term Democratic Sen. Debbie Stabenow is up for re-election in 2018.
Republican candidates include former state Supreme Court Justice Bob Young and Iraq War veteran and business executive John James. Businessman Sandy Pensler also is considering a run.