The Vesting Clause of Article II provides, "The executive Power [of the United States] shall be vested in a President of the United States of America." Proponents of the unitary executive theory argue that this language, along with the Take Care Clause ("The President shall take care that the laws be faithfully executed..."), creates a "hierarchical, unified executive department under the direct control of the President."^[3]

The general principle that the President controls the entire executive branch was originally rather innocuous, but extreme forms of the theory have developed.^[4] John Dean explains: "In its most extreme form, unitary executive theory can mean that neither Congress nor the federal courts can tell the President what to do or how to do it, particularly regarding national security matters."^[4]

According to law professors Lawrence Lessig and Cass Sunstein, "No one denies that in some sense the framers created a unitary executive; the question is in what sense. Let us distinguish between a strong and a weak version."^[1] In either its strong or weak form, the theory would limit the power of Congress to divest the President of control of the executive branch. The "strongly unitary" theory posits stricter limits on Congress than the "weakly unitary" theory.^[1]

Some scholars oppose even the "weakly unitary" theory and favor creating a plural executive, as in the many state governments that separately elect an attorney general.^[2] However, those scholars acknowledge that a constitutional amendment would be required to eliminate the federal unitary executive.

Proponents of a strongly unitary theory argue that the president possesses all of the executive power and can therefore control subordinate officers and agencies of the executive branch. This implies that the power of Congress to remove executive agencies or officers from Presidential control is limited. Thus, under the strongly unitary executive theory, independent agencies and counsels are unconstitutional to the extent that they exercise discretionary executive power not controlled by the president.^[3]

The judicial branch implications are that a part of the executive branch cannot sue another part because "the executive cannot sue himself." If the federal courts were to adjudicate disputes between executive agencies, it would violate the doctrine of separation of powers.^[5]