Thanks to Rudy Giuliani’s report that special prosecutor Robert Mueller told him he couldn’t legally indict President Trump, we are again confronted with a question of constitutional law for which there is no settled answer: Can a sitting president be indicted for criminal activity? There is no precedent for such an indictment, but there is much debate among scholars and lawyers about whether it would be legal to do so.

Justice Department policy and two internal memos—one dating back to Watergate and the other from the Clinton era—suggest that the answer is no. This view is contested by various scholars, and most recently Sen. Richard Blumenthal (D-Conn.), who believes a president could be indicted and the trial postponed until after the president leaves office. Who is right?

Let’s start with the common ground. All agree that impeachment—which, if successful, turns a sitting president into an indictable ex-president—resolves the issue. But impeachment is highly unlikely in current circumstances, given that it requires a 2/3 vote in the Senate to convict. It is unimaginable that Republicans, who have tightly yoked their party to Trump, will be willing to impeach, and so the question of whether a sitting president can be indicted remains live.

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