What access Elon Musk has to closely-guarded government data – including sensitive information it has collected about and from the American public – is a key battlefront in the ongoing and quickly-moving legal war over how President Donald Trump has sought to drastically transform the federal bureaucracy.

The U.S. Department of Justice has agreed to limit Elon Musk and the Department of Government Efficiency's access to the Treasury Department's federal payment system.

Elon Musk will work under President Donald Trump as a “special government employee,” designating Musk as an unpaid employee of the federal government with fewer restrictions than full-time employees, according to the White House, as Musk’s so-called Department Of Government Efficiency has involved itself in multiple federal agencies in recent days.

Elon Musk is testing the limits of legal and ethical restrictions on the role of special advisers in U.S. presidential administrations, according to some legal experts and lawmakers who oppose the billionaire's mission against what he deems wasteful government spending.