“Plenary Authority”
Why That Phrase Should Terrify Every American
When former Trump adviser Stephen Miller declared this week that President Trump has “plenary authority,” he didn’t invent a new legal term, but he did resurrect one of the most dangerous ideas in constitutional history.
“Plenary” comes from the Latin plenus, meaning “full” or “complete.” In law, it describes power that is absolute within a specific domain. Unqualified, total, and not subject to review. A court may have “plenary jurisdiction” over a case; Congress has been said to hold “plenary authority” over immigration or Indian affairs because the Constitution grants it exclusive legislative control in those areas.
But when someone claims that a president has plenary authority, the meaning shifts from technical to terrifying. It implies a head of state whose powers are bound only by will, not by law.
Where did this phrase come from? The idea of plenary power appeared in the US in 19th-century Supreme Court decisions, especially those concerning Native American tribes and immigration. In Chae Chan Ping v. United States (1889)—the “Chinese Exclusion Case”—the Court held that Congress possessed “plenary power” to exclude immigrants, even overriding treaties. Later rulings extended that logic: if a power was “inherent in sovereignty,” it could be exercised without meaningful judicial limits. In other words, the Court was saying that if a power was part of what it meant to be a sovereign nation, the government could use that power however it wanted, without the courts stepping in to stop it.
Those cases have long been criticized for endorsing unchecked governmental authority. They sit uneasily beside the Constitution’s central premise that no branch holds unlimited power. The framers, scarred by monarchy, deliberately divided authority among executive, legislative, and judicial branches and reserved the bulk of governance to the states and to the people.
So when modern politicians revive the term “plenary authority” to describe presidential power, they are not citing a healthy constitutional tradition. They are reaching for one of its most illiberal remnants.
So why is the White House Chief of Staff using this phrase now? Miller’s comment came as the administration moved National Guard units into multiple U.S. cities: Chicago, Portland, and parts of Oregon, against the objections of local officials. It’s being used in the wake of using the National Guard and Federal overreach in Los Angeles, Washington D.C., and other places where ICE raids have reached an epidemic level. The White House has justified these deployments as necessary to restore order and assist immigration enforcement, citing the Insurrection Act and “inherent executive authority.”
The fact that Stephen Miller froze up after his Freudian slip tells us a lot about how much he believes the President plans to use plenary authority and that he shouldn’t have said it out loud.
At the same time as this is happening, the government is in a partial shutdown. Oversight offices within the Department of Homeland Security are furloughed, yet ICE operations continue. Federal detention centers remain active with minimal supervision. In Washington, D.C., the Metropolitan Police Department was recently placed under federal control, a move framed as an anti-crime measure but viewed by critics as a test of centralized policing power.
Miller’s invocation of “plenary authority” lands like a thunderclap in this atmosphere. It suggests that the president’s control over security forces, military, immigration, and police is not merely broad but absolute.
The claim of plenary authority by the Executive Branch is dangerous. The U.S. Constitution gives the president significant power: commander in chief of the armed forces, chief executive of the federal government, and the authority to “take care that the laws be faithfully executed.” But none of those powers are plenary. Each is hemmed in by Congress’s control of funding, the courts’ power of review, and the states’ sovereign rights.
Declaring plenary authority collapses those boundaries. It asserts that checks and balances are optional, an argument more common in authoritarian systems than in republics.
History shows where such claims lead. In 1952, President Harry Truman seized the steel industry during the Korean War, citing inherent executive power. The Supreme Court struck him down in Youngstown Sheet & Tube Co. v. Sawyer, warning that presidential authority “must stem either from an act of Congress or from the Constitution itself.” Truman accepted the ruling and returned the mills, reinforcing that even wartime presidents are not kings.
Miller’s framing rejects that tradition. It recasts the executive as a sovereign unto himself, free to deploy troops domestically, direct federal arrests, ignore court rulings, act without congressional approval, and override state objections at will. In a moment when partisanship has already hollowed out Congress and shown the Supreme Court is impotent to stop President Trump, that rhetoric becomes more than theory; it becomes license.
To continue with this discussion, we have to connect some dots. These obviously aren’t all the dots, but we need to discuss ICE, the Guard, and the Shutdown. Each recent development makes more sense through this lens.
National Guard deployments: Governors have protested the presence of out-of-state Guard units in their jurisdictions, arguing that policing belongs to local control. The federal government’s insistence that it can override them rests implicitly on a claim of plenary executive power over “national security.”
ICE operations: During the shutdown, ICE continues detaining and transferring migrants while internal watchdogs are idle. A government operating without oversight is, by definition, exercising power closer to plenary than accountable.
Federalization of D.C. police: The capital city, which lacks statehood, has become a testing ground for direct federal control of local law enforcement, another assertion that the executive can bypass normal layers of governance.
None of these actions alone dismantles democracy. But together, they normalize the idea that the president can act first and explain later, a pattern political scientists call executive aggrandizement. Executive aggrandizement is a political science term that means a president or leader slowly gathers more and more power for themselves. Often this is done by bending rules, ignoring limits, or weakening other branches of government. It usually happens gradually and legally, not through a coup, so people don’t notice until the balance of power has already shifted. In short, it’s when the executive branch quietly makes itself stronger at everyone else’s expense. Executive aggrandizement is the hallmark of democratic erosion.
The word “plenary” appeals to certain groups of people, authoritarians among them. The word carries a kind of magic. To say a power is plenary is to imply it is complete, not subject to debate. It flatters the strongman’s image of decisive rule, government without the mess of negotiation.
Fascist leaders in the 20th century understood this linguistic power. Mussolini’s Parliament granted him “full powers” to legislate by decree. Hitler’s Enabling Act did the same. Both regimes began with legalistic justifications that sounded temporary and necessary. Within a few years, they were permanent.
If that sounds familiar, it should. In Star Wars: Episode II – Attack of the Clones, Chancellor Palpatine is given “emergency powers” by a fearful Senate to deal with a manufactured crisis. He promises to relinquish them once peace is restored, but never does. What George Lucas captured wasn’t just space fantasy; it was a direct echo of how real republics have fallen. Authoritarians rarely seize power outright. They’re granted it, legally, by people who think the danger is temporary.
That is why claims of plenary presidential power should alarm every constitutionalist, regardless of party. The Founders designed a system allergic to absolutism. George Washington twice rejected the chance to extend his power; Abraham Lincoln, even during the Civil War, sought congressional ratification of emergency measures. The test of a republic is not whether leaders can seize more power but whether they choose restraint.
There’s an irony worth noting here. In the Catholic tradition, the word plenary means something very different. A plenary indulgence is the complete forgiveness of the temporal consequences of sin, a total cleansing offered by God’s mercy, not by human will. It is an act of grace, not domination. The fullness it describes is spiritual, not political. When someone like Stephen Miller uses plenary to describe a president’s power, it inverts the word’s meaning. In faith, plenary means wholeness and restoration; in politics, it now means control and submission. One fills the soul with grace; the other empties the republic of restraint.
There is a broader pattern of Democratic erosion here, though. Political scientists describe three stages by which democracies slide toward authoritarianism:
Delegitimizing referees—attacking courts, the press, or watchdogs as enemies.
Rule manipulation—changing laws and norms to entrench incumbents.
Selective enforcement—using state power against opponents.
The United States in 2025 is showing signs of all three. Courts and journalists are dismissed as partisan. Election laws are rewritten at the state level to narrow participation. Federal law enforcement has been wielded against political targets, while the shutdown disables oversight mechanisms. The rhetoric of plenary authority ties these trends together and provides the theoretical justification for them: if the president’s power is total, then any use of that power is legitimate by definition.
Strong leaders promise order in moments of uncertainty. But history reminds us that order imposed without accountability is the prelude to tyranny. The framers knew that, which is why they built a republic, not a throne. The word “plenary” may sound abstract, but its meaning is simple: unchecked power. And unchecked power, no matter who holds it, has never ended well for a free people.