Senate Majority Leader John Thune (R-S.D.) and Sen. Tim Scott (R-S.C.) on Thursday endorsed Rep. Kevin Hern (R-Okla.) in the race to succeed outgoing Oklahoma Sen. Markwayne Mullin (R). In a release by the National Republican Senatorial Committee, which Scott chairs, Thune called Hern “a proven conservative leader and fighter for Oklahomans” in the House....