"If you send Jon and the reverend to Washington, those $2,000 checks will go out the door," Biden said Monday while campaigning in Atlanta on the eve of the election. "And if you send Senator Perdue and Loeffler back to Washington, those checks will never get there. It's just that simple. The power is literally in your hands."
18 U.S. Code § 597 - Expenditures to influence voting
Whoever makes or offers to make an expenditure to any person, either to vote or withhold his vote, or to vote for or against any candidate; and
Whoever solicits, accepts, or receives any such expenditure in consideration of his vote or the withholding of his vote—
Shall be fined under this title or imprisoned not more than one year, or both; and if the violation was willful, shall be fined under this title or imprisoned not more than two years, or both.