Sen. Ben Nelson (D-Neb.) says he would like to see former Sen. Bob Kerrey (D-Neb.) run for Sen. Chuck HagelCharles (Chuck) Timothy HagelOvernight Defense: Latest on historic Korea summit | Trump says 'many people' interested in VA job | Pompeo thinks Trump likely to leave Iran deal Should Mike Pompeo be confirmed? Intel chief: Federal debt poses 'dire threat' to national security MORE's (R-Neb.) now-vacated Senate seat and that he will not endorse a presidential candidate until the convention.