PHILADELPHIA (CBS) – Former Pennsylvania Governor Ed Rendell believes Senator Pat Toomey made a mistake in his re-election bid by not clearly defining his support, or lack thereof, for Republican nominee.

Rendell told Rich Zeoli on Talk Radio 1210 WPHT that Toomey’s lack of clarity could cost him the race against Democratic challenger Katie McGinty.

“I think there are going to be some Donald Trump voters who are not going to vote for Pat Toomey because he, sort of, went south on Donald Trump. Will that help Pat Toomey in the suburbs? I think he’s not going to get the maximum amount of help in the suburbs because in the suburbs, they wanted to hear him say he wasn’t going to vote for Donald Trump, so I think, in some ways, Pat may have gotten the worst of both worlds by that decision.”

He thinks the top-of-the-ball presidential election between Hillary Clinton and Donald Trump will offer a good indication as to who is likely to emerge in the Senate race.

“I think that race is going to be very close. I think if Hillary Clinton wins by four or more points, then Katie McGinty will definitely win. If Hillary Clinton is somewhere at three or two, it will be close and in if Hillary Clinton is below two or, of course, doesn’t win, I think Pat Toomey is fairly likely to win.”