"Casey was running in a very tough environment for incumbents. ... People are sick of Washington and politics as usual," a political analyst tells Pittsburgh's Action News 4.

Pennsylvania’s U.S. Senate race between three-term Democratic Sen. Bob Casey and Republican challenger David McCormick will help determine control of the chamber Tuesday in a battleground state contest that is one of the nation’s most expensive this year.

As of Wednesday afternoon, U.S. Senator Bob Casey and his Republican opponent Dave McCormick remained in a tight race that is too close to call.