Trump headlines both nights of the GOP's first-ever midterm convention starting Wednesday, a historical oddity not seen since 1982. Approval ratings hit new floors: New polls show Trump at 36% and 33%, with even GOP voter support slipping as the party braces for a "shellacking." The great no-show: Of 60 battleground candidates contacted by CBS, only four confirmed attendance, while 51 ignored the invite entirely—opting to...