A new poll has for the first time given Republican challenger Dave McCormick the lead in the Pennsylvania Senate race against Bob Casey Jr.

A top political handicapper shifted its rating on Monday in the pivotal Pennsylvania Senate race, signaling dwindling chances for Democratic Sen. Bob Casey's re-election.

For a long term incumbent to be in a toss up, something big is happening in PA,’ one observer said of the race shifting.

The Cook Political Report on Monday shifted the Pennsylvania Senate race into the “toss-up” category and moved the Nebraska Senate contest from likely to “lean Republican”

The U.S. Senate race in Pennsylvania is tightening as two recent polls show incumbent Democratic Sen. Robert P. Casey Jr.’s lead evaporating.