Also known as: separation-of-powers · separation of powers doctrine
Written by attorneys · grounded in primary & secondary sources — see below
The division of governmental authority into three branches of government—legislative, executive, and judicial—each with specified duties on which neither of the other branches can encroach. The doctrine establishes checks and balances to protect against tyranny by preventing any branch from exercising powers assigned to another.
After a federal district court entered final judgment dismissing Sophia Singh's securities fraud suit, Congress enacted a statute directing courts to reinstate all such cases dismissed on timeliness grounds. Singh moved to reinstate her action. The court denied the motion because the statute required reopening a final judicial judgment, violating separation of powers by allowing legislative interference with completed cases.
Sabrina Shah, a married woman, challenged a state statute criminalizing contraceptive use after her physician faced prosecution for providing advice. Shah argued the law invaded a protected zone of privacy. The court invalidated the statute because legislative enactment of the prohibition exceeded constitutional bounds without proper grounding in enumerated powers.
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Samuel Soto, a church member denied a building permit, sued under a federal statute purporting to restore broad free-exercise protections after the Supreme Court narrowed them. The city defended on the ground that the statute altered constitutional meaning. The court struck down the statute because Congress lacked authority to redefine judicial interpretations of constitutional provisions.
Stella Shapiro sued six federal narcotics agents for damages after an allegedly unconstitutional search of her apartment. The agents moved to dismiss, arguing no statutory cause of action existed. The court recognized an implied remedy because denying all relief would leave executive misconduct unchecked by judicial oversight.
Serena Soto, a shareholder, sought to preclude Parklane Hosiery from relitigating issues already decided against it in an SEC enforcement action. The company objected that nonmutual offensive estoppel would undermine jury-trial rights. The court permitted estoppel because efficiency gains did not override the constitutional allocation of fact-finding roles between judge and jury.
Selena Singh and her partner challenged a state law barring same-sex marriage after their out-of-state marriage was denied recognition. State officials defended the law as within traditional legislative authority. The court invalidated the ban because judicial enforcement of substantive due process limits prevented legislative override of fundamental rights.
Congress may change substantive law for pending or future cases but may not direct courts to reopen and reinstate cases with final judgments. Such legislation interferes with completed judicial decisions and violates the structural division of authority between the legislative and judicial branches.
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Congress violates the separation of powers when it retains control over execution of the laws—such as by giving a review board composed of members of Congress veto power over decisions of an executive or local authority—because such a scheme either creates an unconstitutional legislative veto or improperly assigns executive power to legislators.
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Executive agencies may implement existing statutes but cannot promulgate new, generally applicable rules that function as legislation. Any attempt to do so through executive memorandum alone exceeds the authority vested in the executive branch.
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…of the basic values that underlie our society, and wise appreciation of the great roles [of] the doctrines of federalism and separation of powers.” Griswold v. Connecticut , 381 U.S. 479, 501 (1965) (Harlan, J., concurring in judgment). B The majority acknowledges none of this doctrinal background, and it is easy to see why:…