Democratic U.S. Sen. Bob Casey of Pennsylvania and Republican challenger David McCormick have held the first debate in their race for a swing-state seat.

I'm the underdog,” David McCormick told NewsNation’s Leland Vittert in a one-on-one interview for “On Balance.”

Pennsylvania incumbent Sen. Bob Casey Jr. (D) and Republican challenger David McCormick will take the debate stage Thursday evening in Harrisonburg, Pa., as Democrats try to prevent