At least that’s the conclusion of Jennifer Duffy of the Cook Political Report.
While Duffy recognizes that blue state Senators in presidential years were always going to have difficulty this is not the reason for the change.
“Not all rating changes are created equal,” she writes. “Some changes happen when a first-tier candidate gets into a race and instantly makes it more competitive. Others occur because an incumbent retires, rendering the open seat more vulnerable. Still other rating changes are made in the wake of an event significant enough to alter the trajectory of a race. Finally, some races move into more competitive categories not because of anything specific to that race or to the candidates running but because of the overall political environment. This is the case in our two latest rating changes.”
The other major problem is no one knows what ultimate effect a Trump nomination will have on the rest of the ticket since this would be an unprecedented situation.
“Is it possible for Toomey and Portman to outperform the Republican presidential nominee and go on to win?,” Duffy writes. “Yes, but it is very difficult. The closer the presidential race is in these states, the more likely that can happen. Conversely, the wider the margin of victory at the top of the ticket, the less likely a Portman or a Toomey can survive.”