Democrat Katie McGinty is vying to unseat GOP Sen. Pat Toomey.
Rubio and Murphy will square off after winning their respective primaries Tuesday night.
Democrat Katie McGinty has led incumbent Sen. Pat Toomey in most of the recent polls.
McCain fended off controversial attacks by state Sen. Kelli Ward.
Patrick Murphy rode the support of national Democrats to beat Alan Grayson.
Rubio defeated Carlos Beruff, who loaned his campaign more than $8 million.
Devin Henry 08/30/16 11:41 AM EDT
“They want to put us good-working, hard-working coal miners out of jobs,” a miner says.
The move is a sign that Dems are growing pessimistic about Ted Strickland’s chances.
Democrat Ted Strickland is trying to unseat GOP Sen. Rob Portman.
The former presidential candidate is lending a hand to help Democrats retake the Senate.