• Elizabeth Warren wants President-elect Trump to set conflict-of-interest rules for Elon Musk.
• Warren called any lack of rules an "invitation for corruption on a scale not seen in our lifetimes."
• Musk is set to play an influential role in Trump's second term as a co-lead for the DOGE.

Sen. Elizabeth Warren on Monday asked President-elect Donald Trump to set conflict-of-interest rules that would apply to Tesla CEO Elon Musk, who's set to take on a high-profile role as a co-lead of the Department of Government Efficiency (DOGE).

The Massachusetts Democrat and former 2020 presidential candidate sent the letter to Trump's transition team, according to The Washington Post, noting that the team's members have to adhere to an ethics policy that compels them to "avoid both actual and apparent conflicts of interest."

Musk, who spent over $250 million to help elect Trump and boost other GOP candidates ahead of the 2024 general election, has been one of Trump's most omnipresent confidants in recent months, accompanying the president-elect on trips and sitting in on his talks with world leaders.

Trump has tasked Musk and former GOP presidential candidate Vivek Ramaswamy with cutting government waste through the DOGE. The pair have said they want to cut $2 trillion from the federal budget.

"Putting Mr. Musk in a position to influence billions of dollars of government contracts and regulatory enforcement without a stringent conflict of interest agreement in place is an invitation for corruption on a scale not seen in our lifetimes," Warren said in her letter.

"Currently, the American public has no way of knowing whether the advice that he is whispering to you in secret is good for the country — or merely good for his own bottom line," she continued.

Trump spokesperson Karoline Leavitt in a statement to Business Insider responded to Warren by praising Musk's influence and criticizing the Democratic lawmaker. Leavitt called Warren a "career politician whose societal impact is 1/1024th of Elon Musk's" and said Trump's transition team was adhering to high ethical guidelines.

Musk was one of Trump's highest-profile surrogates during the presidential race, spending weeks campaigning for the president-elect in pivotal Pennsylvania, which Trump would go on to win en route to a national victory.