HARRISBURG, Pa. (AP) — 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. Casey tried to drive home the message that McCormick is a carpetbagging ex-hedge fund CEO. McCormick painted Casey as a weak career politician. Each candidate also repeatedly accused the other of lying. One thing the candidates agreed on was opposing the sale of U.S. Steel to Japan’s Nippon Steel. Meanwhile they disagreed on preserving the Senate filibuster. Casey supports ending it so senators vote on big issues. McCormick said the filibuster protects moderation.