The Supreme Court has ruled, 9-0, that you cannot allow voting to continue after election day:

“When the federal statutes speak of ‘the election’… they plainly refer to the combined actions of voters and officials meant to make a final selection of an officeholder… By establishing a particular day as ‘the day’ on which these actions must take place, the statutes simply regulate the time of the election, a matter on which the Constitution explicitly gives Congress the final say.” Foster v. Love, 522 U.S. 67, 71-72 (1997)

If an election is consummated after Election Day, this also violates the statute, and such behavior, along with State legislation that encourages it, is preempted by 3 U.S.C. § 1. The logic of such a prohibition goes directly to the heart of the evils Congress sought to nullify by creating a uniform Election Day.

Single day elections curtail a distortion of the voting process by concealing results that might influence later voting. The “object” of 2 U.S.C. § 7, as noted by the Supreme Court, was to remedy multiple evils involved with non-uniform voting. Therefore, under the unanimous holding in Foster v. Love, federal elections consummated before, and after, Election Day, are preempted by Congressional statutes.

Federal law absolutely prohibits any voting to continue after election day, as did state law in Pennsylvania. It's time for this nonsense to stop.

Also, if someone can figure out a way to distill this into a digestible meme or infographic format, you'd be doing God's work.