In order to help former President Trump, who is running for the next president of the United States, Musk promised that he would "spend $1 million a day" to randomly reward registered voters who participated in the petition.

The U.S. Department of Justice has sent a warning letter to American businessman Elon Musk.

However, CNN said that some American legal experts pointed out when Musk made this decision that Musk's move may violate the U.S. federal election law, because the law prohibits others from registering to vote by giving money, and Musk's activity of spending money to reward people for participating in his petition is suspected of being illegal because it is only for registered voters.

The New York Times said that according to two people familiar with the matter, the U.S. Department of Justice's public integrity team responsible for investigating violations of election laws has sent a letter to Musk's Super PAC, warning that his actions may be suspected of being illegal.

The newspaper also said that the U.S. Department of Justice has also sent such warning letters to other commercial institutions and organizations with similar problems. The newspaper also mentioned a case that happened in 2010: At that time, Vince McMahon, the owner of the World Wrestling Entertainment (WWE) in the United States, was warned by the U.S. Department of Justice for giving free WWE-themed clothing to registered voters in the United States, because this action also constituted an illegal situation of giving money to people to vote.

However, the newspaper said that such warning letters usually do not state what actions the Department of Justice will take next, but force the recipient to make corrections through warnings to comply with legal requirements.