It's not clear who would prevail.
Special counsel Robert Mueller’s threat to subpoena President Trump in the Russia investigation sets up a potentially historic clash that could reach the Supreme Court, legal experts say — and it’s not clear who would prevail.
Mueller has been negotiating an interview with Trump for weeks, but the president’s legal team has been wary of granting the request, reportedly seeking to place conditions on the questions asked and the format and length of the encounter.
Trump in the past has said he wanted to talk to Mueller as a way of wrapping up an investigation that the president has termed a “witch hunt,” but he soured on the prospect after the FBI raided the offices of his longtime personal attorney, Michael Cohen.
Since then, according to The Washington Post, Mueller has floated the prospect that he could subpoena the president to force him to appear.
Ty Cobb, a member of Trump’s legal team who is now on his way out of the White House, told ABC News on Wednesday that it is an “open question” whether a special counsel can compel a sitting U.S. president to testify.