Bob Casey is a lazy useless politician. The only reason he is not a garbageman in Scranton is that his father was a popular governor of Pa. a long time ago. His first elected office was Auditor General of Pennsylvania. I recall a review of his performance indicated that he actually was in his office working less than 60 days a year. Since he has been in the Senate he has simply done what the party leadership tells him to do. He has never had an original thought. In 2012 he won re-election because the Republican ran a total stiff (Tom Smith) against him. Casey is ripe for the picking in 2018.
To beat Casey the Republicans need to run a decent candidate. The man to run is Lou Barletta. He is an energetic conservative from Hazleton. He was a superb mayor and now is a great US representative. Trump has contacted Barletta and has asked him to run. See link. Let's hope he runs and sends Casey back to Scranton for a permanent vacation.