Musk, the world’s richest man, announced the contest on Saturday in Pennsylvania, one of the seven “swing states” that will likely determine who will become the next US president - Donald Trump or Kamala Harris.
Musk, a Trump supporter, announced plans to give US$1mn to one registered voter in a swing state every day until the US election on Nov 5.
CNN and 24sight News said the letter from the Justice Department to Musk’s political action commitee warns that the US$1mn sweepstakes may violate federal law, which prohibits paying people to register to vote.
The Justice Department declined to comment.
The winners of the contest are chosen at random but they must be registered voters. They are also required to sign a petition that supports “free speech and the right to bear arms.”
Danielle Lang, a professor at Georgetown Law School who specializes in election law, told AFP earlier this week that the contest could be “subject to civil or criminal enforcement by the Department of Justice.”
“It is illegal to give out money on the condition that recipients register as voters,” Lang said.
“As the terms of this ‘contest’ to win $1 million require the recipient to be a registered voter in one of seven swing states (or to register if they have not already), the offer violates federal law,” she said.
Tesla and SpaceX CEO Musk has pulled out all the stops in recent weeks to support former president Trump, including donating US$75mn to a pro-Trump political action committee and appearing at campaign rallies.