516 The reticence of the Constitution respecting removal left room for four possibilities: first, the one suggested by the common law doctrine of “estate in office,” from which the conclusion followed that the impeachment power was the only power of removal intended by the Constitution; second, that the power of removal was an incident of the power of appointment and hence belonged, at any rate in the absence of legal or other provision to the contrary, to the appointing authority; third, that Congress could, by virtue of its power “to make all laws which shall be necessary and proper,” etc., determine the location of the removal power; fourth, that the President by virtue of his “executive power” and his duty “to take care that the laws be faithfully executed,” possesses the power of removal over all officers of the United States except judges.