Musk announced the $1 million giveaway at an event in Harrisburg, Pa., on Saturday. The event was part of a tour supporting Trump.

“I have a surprise for you," Musk said shortly before bringing out a giant check. "We are going to be awarding $1 million to people who have signed the petition — every day, from now until the election.”

"If you look at the conditions, you must be a registered voter," Hasen said. "And so this is essentially a lottery that's open only to people who register to vote. So it’s either an incentive for someone to vote or it’s a reward. And either way, it violates federal law."

He calls Musk's actions "clearly illegal" because it violates statute 52 U.S.C. 10307(c) and the Department of Justice’s election manual.

Hasen said willful violation of statute 52 U.S.C. 10307(c) comes with a $10,000 fine and up to five years in prison.

"I don't think it would be likely that he would suffer such a serious fine," Hasen said of Musk. "Although, if he was warned that this is illegal activity and continued to do it, I think that would create a different kind of situation."