Elon Musk has inserted himself into an American presidential election more than perhaps any other uber-wealthy person in modern history. There is no question that one of the world’s richest people is going to great lengths to speak and spend Donald Trump into the White House.

But could Musk’s latest gambit venture into illegal territory — by paying people to, in effect, register to vote? That’s the contention of some legal experts, who say Musk’s newly announced daily $1 million prize to randomly selected registered swing-state voters who sign a petition for his America PAC appears to be a bribe.

It’s not totally clear that what Musk is doing is illegal. And even if the case went to court, the Supreme Court has recently taken a narrow view of what constitutes political bribery. But Musk’s efforts at the very least exploit election laws by marrying a voter-registration push and advocacy for Trump with a sweepstakes.

Musk announced the $1 million prizes Saturday. He was already offering registered voters $100 to sign the petition and $47 for each registered swing-state voter they got to sign the petition. He’s now offering the daily $1 million prize to a randomly selected registered voter who signs the petition.

Election law expert Richard L. Hasen of the UCLA School of Law said over the weekend that the scheme is “clearly illegal.” Hasen pointed to 52 U.S.C. 10307©, which says someone who “pays or offers to pay or accepts payment … for registration to vote” has broken the law. The crime carries maximum penalties of a $10,000 fine and five years in prison.

The Justice Department’s election crimes manual describes this crime as “bribery” and explicitly includes “lottery chances” as a prohibited reward. The manual distinguishes such rewards from things like giving people a ride to the polls, because they induce people who wouldn’t otherwise have voted or registered to vote to do so.

“The statute rests on the premises … that those who choose to vote have a right not to have the voting process diluted with ballots that have been procured through bribery,” the manual says, “and that the selection of the nation’s leaders should not degenerate into a spending contest, with the victor being the candidate who can pay the most voters.” The key distinction in Musk’s scheme is that he’s not explicitly paying people to vote or even register to vote, but rather to sign a petition — a petition featuring a brief statement affirming support for the First and Second amendments to the Constitution.

“The First and Second Amendments guarantee freedom of speech and the right to bear arms,” the petition states. “By signing below, I am pledging my support for the First and Second Amendments.”

Bradley Smith, a former Republican appointee to the Federal Election Commission, told the New York Times that because of this distinction, “I think he comes out OK here.”