Mike Pence poked fun at predecessor Joe Biden on Friday for calling himself the vice president of the United States. Speaking at the House Republican retreat in Baltimore, Pence said he heard Biden had referred to himself as the “vice president” during the Democratic debate in Houston on Thursday night. Biden, of course, served as No. 2 under former President Barack Obama. The usually straight-laced Pence said, “Let me be clear: I am the vice president of the United States of America.” It was probably one of Biden’s least offensive gaffes at the debate, where he delivered several rambling answers and non sequiturs.