Twenty-eight words, added last to the Bill of Rights, carry the entire architecture of the American union. This is the story of why the framers thought they were necessary — and why a fierce argument over a single missing word still echoes through the Supreme Court today.
What the Amendment Actually Does
The Tenth Amendment does not grant a single new power. It does the opposite: it states a rule about where power that was never granted in the first place is presumed to live. The federal government may exercise only the authority the Constitution hands it; everything left over stays with the states, or with the people themselves. In a sentence, it is the closing argument for the whole design — a declaration that the national government is one of limited and enumerated powers.
To understand why Americans in 1791 felt they needed to write that down — when the framers of 1787 had insisted it was already obvious — you have to go back well before the Revolution, to a century of colonists who had grown used to governing themselves.
An Inheritance of Self-Government
The reserved-powers idea did not appear in 1791. It was the habit of mind of people who had been running their own affairs for generations. From the earliest colonial compacts onward, communities in America assumed the everyday business of life — courts, roads, schools, churches, marriage, property, the local peace — belonged to them, not to a distant authority across an ocean.
That instinct was reinforced by the political philosophy the founders read closely. John Locke taught that legitimate government rests on the consent of the governed and exists to secure rights people already hold by nature. Montesquieu argued that liberty survives only where power is divided, and praised the "confederate republic" that could be large enough to defend itself yet small enough in its parts to stay free. When the colonies declared independence in 1776, the new states immediately wrote constitutions and declarations of rights asserting that authority flowed up from the people and that the states held the "sole and exclusive right" of regulating their own internal affairs.
"That the people of this State have the sole, exclusive and inherent right of governing and regulating the internal police of the same."
— Pennsylvania Constitution of 1776, Declaration of Rights, Article III · Avalon Project
This is the seedbed of the Tenth Amendment: a settled expectation, written into the first state constitutions, that internal self-government was the default and any central power was the exception.
The Articles of Confederation & the Word "Expressly"
When the states bound themselves together during the Revolution, they did so as guarded equals. The Articles of Confederation — adopted by Congress in 1777 and in force from 1781 — created a "league of friendship," not a nation. Its second article said the quiet part out loud, and it is the direct ancestor of the Tenth Amendment, with one fateful difference.
"Each state retains its sovereignty, freedom, and independence, and every Power, Jurisdiction and right, which is not by this confederation expressly delegated to the United States, in Congress assembled."
— Articles of Confederation, Article II (in force March 1, 1781) · Avalon Project
Notice the word "expressly." Under the Articles, Congress could do only what was spelled out — nothing by implication. That made the central government almost powerless. It could not tax, could not regulate commerce among the states, and could not compel anyone to do anything. By the mid-1780s the country was drowning in debt, foreign respect was collapsing, states were waging trade wars against one another, and in 1786–87 an armed uprising of indebted farmers in Massachusetts — Shays' Rebellion — showed that the confederation could not even keep order. The lesson many drew was blunt: a union that reserves everything to the states reserves the power to fail.
Enumerated Powers — and a Deliberate Omission
The Philadelphia Convention of 1787 set out to fix this. Its solution was not to abandon federalism but to redesign it: a national government strong enough to govern in defined areas — taxation, defense, interstate and foreign commerce, currency — while leaving the vast field of ordinary life to the states. Crucially, the framers built the new government around enumerated powers. Article I lists what Congress may do; the structure assumes everything unlisted is withheld.
Because of that logic, the Constitution went to the states in September 1787 without a bill of rights. To Federalists this was not an oversight but a point of principle: a government that possesses only listed powers needs no list of things it cannot do, because it was never given the power to do them. Alexander Hamilton made the argument famous.
"Why declare that things shall not be done which there is no power to do? Why, for instance, should it be said that the liberty of the press shall not be restrained, when no power is given by which restrictions may be imposed?"
— Alexander Hamilton (Publius), The Federalist No. 84 (1788) · Avalon Project
James Madison reassured the states that the new design left them their proper sphere intact — that federal authority was, by deliberate construction, narrow.
"The powers delegated by the proposed Constitution to the federal government are few and defined. Those which are to remain in the State governments are numerous and indefinite."
— James Madison (Publius), The Federalist No. 45 (1788) · Avalon Project
The Anti-Federalist Alarm
The Federalists' confidence did not persuade everyone. The Anti-Federalists — writing under pen names like Brutus, the Federal Farmer, Centinel, and John DeWitt — looked at the Constitution's broad clauses (the power to tax "for the general welfare," the Necessary and Proper Clause, the Supremacy Clause) and saw a central government that would, over time, swallow the states whole. Promises about "enumerated powers," they warned, would mean little once Congress claimed implied powers to reach almost anything.
"A little attention to the powers vested in the general government, will convince every candid man, that if it is capable of being executed, all that is reserved for the individual states must very soon be annihilated."
— Brutus I (attributed to Robert Yates), October 18, 1787 · Teaching American History
Their demand was concrete: put the limits in writing. A free people, they argued, secures its rights expressly rather than trusting the restraint of those in power. This produced a revealing paradox. The Federalists said a reserved-powers clause was unnecessary because the structure already accomplished it; the Anti-Federalists said that was precisely why it should be safe to add. The argument over whether to declare the principle in words would shape both the ratification of the Constitution and the wording of the amendment that followed.
The Price of Ratification
By 1788 the Constitution was hanging by a thread in the largest states. To win ratification, Federalists struck a bargain: ratify now, and amendments — including an explicit reservation of powers to the states — will follow in the new Congress. Several state conventions did not merely hope for this; they wrote out the very language they expected, attaching recommended amendments that read almost like the Tenth Amendment to come.
"That each state in the union shall, respectively, retain every power, jurisdiction and right, which is not by this constitution delegated to the Congress of the United States, or to the departments of the Federal Government."
— North Carolina, Proposed Amendments to the Constitution, No. I — August 1, 1788 · Avalon Project
Massachusetts, Virginia, New York, and North Carolina all forwarded reserved-powers declarations of this kind. North Carolina went further and refused to ratify until a bill of rights was on its way. The reserved-powers amendment was, in short, the political price of the Constitution itself.
Madison Drafts the Amendments
James Madison — once skeptical that a bill of rights was needed — took up the cause in the First Congress, partly from conviction and partly to honor the ratification bargain and disarm calls for a dangerous second convention. On June 8, 1789, he rose in the House of Representatives and proposed the package that would become the Bill of Rights, including the reserved-powers clause. He was explicit about where the idea came from.
"I find, from looking into the amendments proposed by the state conventions, that several are particularly anxious that it should be declared in the constitution, that the powers not therein delegated, should be reserved to the several states."
— James Madison, Speech in the House of Representatives, June 8, 1789 · The Founders' Constitution
The principle was uncontroversial. What happened next — a fight over a single adverb — would define how the amendment is read to this day.
One Word That Wasn't There: "Expressly"
When the clause reached the House floor in August 1789, Representative Thomas Tudor Tucker of South Carolina moved to insert the word "expressly," so it would read that powers not expressly delegated are reserved to the states — exactly the language of the old Articles of Confederation. Madison rose against it, and the difference he insisted on is the whole interpretive ballgame.
"It was impossible to confine a Government to the exercise of express powers; there must necessarily be admitted powers by implication, unless the Constitution descended to recount every minutia."
— James Madison, Remarks on the future Tenth Amendment, House of Representatives, August 18, 1789 · The Founders' Constitution
The motion to add "expressly" was defeated. That deliberate choice is why the Tenth Amendment is not a return to the failed confederation. By leaving the word out, the framers preserved room for the federal government's implied powers — the authority to use reasonable means to carry out its enumerated ends. The Tenth Amendment confirms that undelegated power is reserved; it does not deny that some powers are delegated by implication. Madison won the wording. Generations of judges have argued over what it lets the national government do ever since.
December 15, 1791 — "…or to the people"
Congress passed twelve proposed amendments on September 25, 1789. Ten were ratified by the states, and on December 15, 1791, with Virginia's assent, they became part of the Constitution. The last of them was the reserved-powers clause in its final, carefully edited form.
"The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people."
— Tenth Amendment, ratified December 15, 1791 · U.S. National Archives
One phrase repays close reading: "or to the people." The amendment does not simply hand undelegated power to state governments. It locates the leftover authority in two places — the states and the people — a reminder that, in the American scheme, government at every level is a trustee, and ultimate sovereignty rests with the citizens who created both.
Truism, or Shield?
Because the framers refused the word "expressly," the Tenth Amendment has always carried two readings. One sees it as a truism — a statement of the obvious that adds nothing the structure didn't already provide. The other treats it as a real shield, an enforceable limit on what the national government may demand of the states.
The pendulum has swung hard between them. In McCulloch v. Maryland (1819), Chief Justice Marshall read federal power expansively and held the amendment no barrier to a national bank. During the New Deal the Court called it merely declaratory — in United States v. Darby (1941) it famously dismissed the Tenth as "but a truism." Then, beginning in the 1990s, a federalism revival gave the amendment new teeth: in New York v. United States (1992) and Printz v. United States (1997) the Court built the anti-commandeering doctrine — Congress may not force states to enact or enforce a federal program — and applied it as recently as Murphy v. NCAA (2018). The argument the Federalists and Anti-Federalists began in 1788 has, in other words, never ended. It has simply moved into the courtroom — which is why the timeline below runs past 1791 and right up to the present day.