The President can exercise no power which cannot be fairly and reasonably traced to some specific grant of power in the Federal Constitution or in an act of Congress passed in pursuance thereof. There is no undefined residuum of power which he can exercise because it seems to him to be in the public interest.

Summary

This quote emphasizes that the President's authority is limited to what is explicitly granted by the United States Constitution and laws enacted by Congress. The President cannot exercise power based on personal instincts or perceived public interest without a clear constitutional or legislative basis. It promotes the idea that presidential power should be derived from specific, defined sources rather than an ambiguous "residuum" open to interpretation. Ultimately, this principle underscores the importance of checks and balances within the American governmental system.