The Antiquities Act of 1906 authorizes the President to “declare” certain objects “to be national monuments,” and to “reserve parcels of land” to protect those national monuments. The Act does not expressly authorize the President to reduce or rescind a monument established by a prior President under the Act, and recent actions by President Donald Trump raise the question whether the Act impliedly authorizes such reductions or rescissions. The majority of legal scholars who have studied this question have said no, the Act does not grant such implied authority. This Article takes the contrary position. The President’s authority under the Antiquities Act to reduce a monument previously established under the Act is established by (1) past presidential practice; (2) congressional acquiescence; and (3) official opinions of the Attorney General and the Solicitor of the U.S. Department of the Interior. Further, the President’s authority to rescind such a monument (1) follows logically from the President’s power to reduce a monument; (2) reflects the President’s constitutional duty to take care that the Antiquities Act is faithfully executed; and (3) accords with the general rule that prevents the current President from being bound by the acts of predecessors in that office.