WATCH: Lindsey Graham uses Amy Barrett hearing to whine about his Senate rival Jaime Harrison
Sen. Lindsey Graham (MSNBC)

Sen. Lindsey Graham (R-SC) suggested his Democratic challenger was somehow improperly obtaining campaign funds.

Jaime Harrison raised a record-breaking $57 million from July through September, the highest quarterly total for any U.S. Senate candidate in history, and Graham hinted during Amy Coney Barrett's Supreme Court nomination hearing that something was afoul.

"Let's go to Citizens United," Graham said, referring to the landmark campaign financing decision. "To my good friend Sen. [Sheldon] Whitehouse. Me and you are going to come closer and closer about regulating money, because I don't know what's going on out there, but there's a lot of money being raised in this campaign. I'd like to know where the hell some of it is coming from."