As Matthew Whitaker took charge of the Justice Department this week, Democrats and some Republicans questioned the legality of his appointment to serve as acting attorney general. No court has ruled directly on the relevant questions, so the answer isn’t clear.

What do we know?

The Constitution requires the president to obtain the Senate’s “advice and consent” when appointing cabinet members and other principal “officers of the United States.” In dividing the appointment power between the executive and the Congress, the framers hoped to limit cronyism and self-interest.

The Constitution also allows the president to make temporary appointments when the Senate is in recess.

At the same time, the Constitution assigns Congress power to establish methods of appointing various federal officers. The current rules for filling most offices temporarily are spelled out by the Vacancies Reform Act of 1998. At the time, then Sen. Fred Thompson (R., Tenn.) said on the Senate floor the act came partly in response to excesses by the Justice Department.