The U.S. Supreme Court – with its six conservative justices, three of whom were nominated by President Donald Trump – has recently reversed landmark decisions that have long guided American government and society. Over the last few years, the court has stripped federal protection of abortion rights, affirmative action, gun control, and a significant portion of the 1965 Voting Rights Act.

In its highly anticipated decision on June 29, 2026, in the case of Trump v. Slaughter, the court has added the political independence of nominally independent agencies to that list, allowing the president to fire members of the Federal Trade Commission. The ruling overturns a case that had held sway for 91 years.

The court’s 6-3 decision in Slaughter also effectively endorses the unitary executive theory, thereby greatly expanding the power of the president.

As a political science scholar who studies presidential power, I believe the unitary executive theory is perhaps the most contentious and consequential constitutional theory of the past several decades. And its judicial approval threatens to upend much of American governance.

A prescription for a potent presidency

In 2017, Trump complained that the scope of his power as president was limited: “You know, the saddest thing is that because I’m the president of the United States, I am not supposed to be involved with the Justice Department. I am not supposed to be involved with the FBI, I’m not supposed to be doing the kind of things that I would love to be doing. And I’m very frustrated by it.”

The unitary executive theory suggests that such limits wrongly curtail the powers of the chief executive.

Formed by conservative legal theorists in the 1980s to help President Ronald Reagan roll back liberal policies, the unitary executive theory promises to radically expand presidential power.

There is no widely agreed upon definition of the theory. And even its proponents disagree about what it says and what it might justify. But in its most basic version, the unitary executive theory claims that whatever the federal government does that is executive in nature – from implementing and enforcing laws to managing most........

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