Billionaire tech entrepreneur Elon Musk upped the ante this weekend in his bid to get more swing state voters to support Donald Trump in next month's presidential election. At a town hall in Harrisburg on Saturday, Musk presented a $1 million check to one lucky attendee who had signed his online petition championing the Constitution's First and Second Amendments.

Every day from now until the election, Musk claimed he'll be giving out a $1 million check to a randomly chosen petition signer from one of seven states, including Pennsylvania. The Tesla and SpaceX founder held four town halls in the battleground state over the last week, making stops in Delaware and Montgomery counties on Thursday and Friday ahead of Monday's voter registration deadline. 

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All month, Musk and his $75 million America PAC have provoked legal debate about whether he's breaking federal election law by offering sums of money to people who sign his online petition. The drive began with a promise of $47 for registered voters who signed the petition and then referred others to register to vote and sign it. America PAC later raised the sum to $100, offering to mail checks to people simply for signing the petition and nothing else.

Election law expert Richard L. Hasen of the UCLA School of Law was among the first to sound alarm about Musk's voter registration tactics. Since Musk had offered money for signing a petition – not specifically to vote or to register to do so – Hasen said the money offers were "of murky legality."

Federal law classifies vote-buying as a form of bribery when someone "pays or offers to pay or accepts payment either for registration to vote or for voting." Violators face penalties of up to five years in prison and $10,000 fines. 

Hasen said Musk's $1 million sweepstakes "veers into clearly illegal vote buying" because of its terms of eligibility, which required signing the petition by the end of the day Monday. He and other election law experts have noted how this lines up with the voter registration deadlines in both Pennsylvania and Michigan. Musk's town halls have pushed for early and mail-in voting, and the person who received the $1 million check in Harrisburg stood beside a sign that said, "Vote early."

Musk himself said Saturday that the most important part of his message was to "register, register, register" before state deadlines – an emphasis that stood out to some observers. 

“Yes, there’s an additional step in the process (signing the petition), but part of the cash prize turns on voter registration status,” Derek Muller, of the Notre Dame Law School, told the Washington Post. “That’s where the potential illegality comes in; it starts to look like someone who ‘pays … for registration to vote."'

Hasen told NBC News that Musk made a lottery exclusively for registered voters in swing states. 

"You’re creating a lottery where the only people eligible to participate in the lottery are people who register to vote, or are registered to vote, and that’s illegal," he said. 

Does money get people to vote?

During a Sunday appearance on NBC's "Meet The Press," Democratic Pennsylvania Gov. Josh Shapiro called Musk's payments "deeply concerning" and said law enforcement could possibly look into it. Shapiro formerly served as Pennsylvania attorney general and suggested his successor, Michelle Henry, might investigate America PAC's activities in the state.

Henry's office did not respond to a request for comment on Monday. Henry is not running for reelection in November's statewide contest for attorney general.

Robin Kolodny, a political science professor and campaign finance expert at Temple University, said Monday that any prosecution of Musk would need to be handled by the U.S. Department of Justice, whose criminal investigations take precedence over state matters and the civil investigations overseen by the Federal Election Commission.

"The Justice Department is famously opaque," Kolodny said. "What they would do and how they would go about doing it is almost impossible to predict, except I can tell you it would take years. There's unlikely to be any immediate implication."

Kolodny said building a case against Musk would come down to the fine print of his petition.

"If it doesn't say, 'I pledge to vote for Donald Trump,' then I'm not sure you can technically say he's done vote-buying," she said.

Musk's campaigning on behalf of Trump raises larger questions about whether or not giving away money is an effective strategy to increase voter registration and turnout. At his rally on Saturday, Musk said he hopes the petition will get 1 million to 2 million more voters in battleground states to participate in the election. 

Kolodny pointed to research by her colleague, Northeastern University political scientist Costas Panagopoulos, that suggests the average voter doesn't view money as a great political motivator to show up at the polls. Panagopoulos gave people in California the chance to claim money simply to vote in a pair of elections in 2007 and 2010. The offers were made without any preferences given to candidates or parties. Voters were sent postcards that they could take with them to the polls to have validated after they voted and receive anywhere from $5 to $25, in most cases.

"Barely anybody did it. Not even for the $25, when all you have to do is walk over to someone after voting," Kolodny said. "It seemed clear that when he followed up with a survey, people were turned off by the whole notion that this would be a transactional thing."

While the study found that "nontrivial incentives" increased voter participation, nominal amounts of money "failed to effectively raise turnout in elections." Musk's $1 million checks will be given to fewer than 20 people by the time of the election on Nov. 5. 

Kolodny said America PAC is most likely giving out money to people who were already planning to vote for Trump.

"Does (Musk) honestly think that he's going to get anybody that's on the fence who's like, 'I really wasn't sure what I was going to do, but for $100, I'll do it?' I wouldn't bet on that at all," she said. "I would bet on people who are already on every site supporting Trump would be like, 'I'm already going to do it, might as well cash in.'"

Furthermore, Musk is putting his own reputation on the line with people who may write him off if they never end up getting $100 checks in the mail. Kolodny said the odds of winning $1 million from Musk are probably about the same as playing the lottery. 

"Who's really betting that this is all going to come through?" Kolodny said. "Look at the fine print. I can't imagine Musk actually has something that's going to produce."

'A contradictory kind of action'

Kolodny is the co-author of a book (free to download) that aims to inform people about important developments in campaign finance law, how they shape our politics and which types of reform seem to be working better than others.

Ahead of the November election, Musk's visibility is emblematic of headwinds that have more to do with celebrity influence than money.

"We're in this era where Taylor Swift says, 'I'm going to go ahead and endorse somebody.' It goes viral without her having to spend a penny on it, but it has value," Kolodny said. "The bigger issue is whether rich people are enticing politicians or voters into doing something they wouldn't do anyway. That's where things get harder."

Celebrity endorsements and heavy spending by Super PACs aren't necessarily calculated to sway the views of politicians, who likely already have their alignments established. More often, supporting candidates can work to get specific issues prioritized. For Musk, that could mean Trump pushes his regulatory concerns about the auto industry and space higher up on his agenda in the White House, Kolodny said.

Musk's willingness to randomly give money to American voters may be at odds with the policies he and Trump are advocating. Last month, Trump said he would tap Musk to lead a federal Department of Government Efficiency that targets wasteful spending.

"Trump's really going to make (Musk) the director of government waste ethics?" Kolodny said. "This is truly a contradictory kind of action."

Unless there is hard evidence that Musk and America PAC are breaking the law, Kolodny thinks the Justice Department is unlikely to devote significant resources to an investigation.

"What are you going to do right now? It's 15 days to the election," she said. "Exactly how are you going to rein this guy in and get the evidence to support that he's done something that's materially relevant to the election?"