Elon Musk, the billionaire founder of Tesla and Space, is now pledging to donate $1 million a day to voters to sign his political action committee’s petition in support of the Constitution.

The sweepstakes is raising questions and concern among some election experts. They believe it is a violation of the law to link spending money to signing a petition that also requires a person to be registered to vote.

Pennsylvania’s Democratic Gov. Josh Shapiro, the state’s former attorney general, expressed concern about the plan on Sunday.

“I think there are real questions about how he is spending money in this race, how the dark money is flowing not only into Pennsylvania but apparently now into the pockets of Pennsylvanians. “This is deeply concerning,” he said on NBC’s “Meet the Press.”

A closer look at what happened:

What does Musk do?

Musk pledged Saturday that he would donate $1 million a day until the Nov. 5 election to people who support his PAC’s petition in support of the First Amendment, which protects free speech, and the Second Amendment with his right “to “To keep and bear arms.” During an event Saturday in Harrisburg, Pennsylvania, he presented a check to a man named John Dreher. A message with a number for Dreher was not returned Sunday. On Sunday, Musk issued another check.

What is the larger context here?

Musk’s America PAC has begun a tour of Pennsylvania, a key election district. His goal is to register voters who support Trump, whom Musk supported. The PAC is also pushing to win over voters in other key states. It’s not the organization’s first cash offer. Musk posted on Sign the petition.

Trump, campaigning in Pennsylvania on Sunday, was asked about Musk’s giveaway and said, “I didn’t follow through on that.” Trump said he “talks to Elon a lot. He is a friend of mine” and described him as great for the country.

What’s the problem with that?

Some election law experts are raising alarm bells about the giveaways. Brendan Fischer, a campaign finance lawyer, said the latest version of Musk’s giveaway hits a legal limit. That’s because the PAC requires registration as a condition of eligibility for the $1 million check. “There would be little doubt about the legality if every Pennsylvania resident to sign the petition were eligible, but tying payment to registration arguably violates the law,” Fischer said in an email.

Rick Hasen, a professor of political science at UCLA Law School, went a step further. He pointed to a law that prohibits paying people to register to vote or vote. “If he just paid people to sign the petition, it might be a waste of money. But there’s nothing illegal about it,” Hasen said in a telephone interview. “The problem is that the only people eligible to participate in this lottery are those who are registered to vote. And that makes it illegal.”

Michael Kang, an election law professor at Northwestern University’s Pritzker School of Law, said the context of the drawing so close to Election Day makes it difficult to argue that the promotion is anything other than an incentive for people to register to vote.

“It’s not quite the same as paying someone to vote, but it’s so close that we’re concerned about the legality of it,” Kang said.

A message seeking comment was left with the PAC on Sunday, as was a request for comment from the Justice Department.

Can the PAC and Trump’s campaign coordinate?

Typically, coordination between campaigns and so-called super PACs was prohibited. But a recent opinion from the Federal Election Commissioner, who regulates federal election campaigns, allowed candidates and these groups to work together in certain cases, including enforcing election efforts.