At the Wednesday night Republican national debate, Texas Gov. Rick Perry committed what some are calling the biggest gaffe of the campaign so far. Perry began listing off the three government agencies he’s vowed to abolish if elected — but then couldn’t remember the third one on his list.

Gov. Rick Perry: “It’s three agencies of government, when I get there, that are gone: Commerce, Education and the—what’s the third one there? Let’s see.”

Ron Paul: “You need five.”

Gov. Rick Perry: “Oh, five, OK. So, Commerce, Education and the—ummm…”

John Harwood: ”EPA?”

Gov. Rick Perry: ”EPA, there you go. No.”

John Harwood: “Seriously? Is EPA the one you were talking about, or…?”

Gov. Rick Perry: “No, sir. No, sir. We were talking about the, ummm, agencies of government. EPA needs to be rebuilt, there’s no doubt about that.”

John Harwood: “But you can’t name the third one?”

Gov. Rick Perry: “The third agency of government I would do away with, the Education, the, uhhh, Commerce, and let’s see. I can’t. The third one, I can’t. Sorry. Oops.”

Perry later said he was calling for the Department of Energy to be abolished. After the debate, he said he may not have remembered the agency, but he remembers his conservative principles.