The White House has warned Democrats that their planned investigations of President Donald Trump and his administration could cross the line into criminal conduct, in an early confrontation with the incoming Democratic Congress.

White House Counsel Will Scharf sent the warning in a letter dated 9 November to Representative Robert Garcia of California, who will chair the House Oversight Committee when Democrats take control of both chambers of Congress in January. It was not made public until 11 November.

What the letter says

Scharf wrote that the administration "will not be extorted and will not be cowed", and argued that congressional investigations must serve legitimate legislative purposes rather than amount to persecution. He cited the Supreme Court's 1957 ruling in Watkins v. United States, which set limits on congressional inquiries. "Issuing unlawful subpoenas with the intention of depriving citizens of their constitutional rights and privileges may warrant further investigation," Scharf wrote, according to USA Today.

What Democrats plan to investigate

Democrats have signalled they may pursue investigations into Elon Musk, the Trump family's cryptocurrency fortune, the president's construction projects, the Iran war and Defence Secretary Pete Hegseth. Possible witnesses include former Homeland Security Secretary Kristi Noem, current Homeland Security Secretary Markwayne Mullin, border czar Tom Homan and Stephen Miller, the new White House chief of staff.

Why the warning came now

Democrats won control of the House and Senate in the midterm elections on 3 November, and the new Congress convenes in January. President Trump has accused Democrats of "extortion" over the planned probes. Scharf told Newsmax on Wednesday that the administration would "fight vigorously" against what he called a return to "lawfare". The letter is a legal warning, not a court ruling, and no criminal investigation has been opened.