Sen. Ben Nelson (D-Neb.) says he would like to see former Sen. Bob Kerrey (D-Neb.) run for Sen. Chuck HagelCharles (Chuck) Timothy Hagel15 former Defense officials back waiver for Austin to serve as Defense secretary The Hill's Morning Report - Biden asks Congress to expand largest relief response in U.S. history John Kirby to reprise role as Pentagon press secretary under Biden MORE's (R-Neb.) now-vacated Senate seat and that he will not endorse a presidential candidate until the convention.