Although Congress can pass statutes limiting the circumstances under which the president can remove commissioners of independent agencies, if the independent agency exercises any executive powers like enforcement, and most of them do, Congress cannot reserve removal power over executive officers to itself. Constitutionally, Congress can only remove officers through impeachment proceedings. Members of Congress cannot serve as commissioners on independent agencies that have executive powers, nor can Congress itself appoint the commissioners – the Appointments Clause of the Constitution vests that power in the president. The Senate does participate, however, in appointments through "advice and consent", which occurs through confirmation hearings and votes on the president's nominees.