HARRISBURG, Pennsylvania — Sen. Bob Casey‘s (D-PA) campaign against Republican challenger Dave McCormick to represent Pennsylvania in the U.S. Senate has been largely fought on the airwaves and online, with McCormick in particular developing a reputation for viral social media posts.

But the two men met in person in Harrisburg, Pennsylvania, on Thursday for the first of their two debates before November’s election, a high-stakes moment for their respective campaigns in a race that will help decide the Senate majority.