Republican outside group launches an ad attacking Democrat Braley as the GOP nominee is off the trail.
Tennessee state Rep. Joe Carr has picked up the conservative talk-radio host's endorsement.
Thomas Ravenel filed 17,000 signatures on Monday, topping 10,000 needed for the S.C. ballot.
At end of day, Portman predicts "bare majority" for GOP.
Kingston and Perdue used the lone opportunity ahead of next Tuesday to wage personal attacks.
Paul Hollis (R) dropped out of the race Monday, which could boost another Tea Party hopeful.
The former senator highlights his own military service in the ad.
GOP hopeful raised $2.28 million to Democratic incumbent's $1.5 million from April to June.
There's no easy solution for Senate candidates trying to tackle the immigration crisis.