Did Texas reserve a right to leave when it joined the union?

Yes, in the way that actually matters under the law, though not in the cartoon version you may have heard. The popular legend that Texas signed a one-of-a-kind deal letting it leave anytime is not accurate, and we will not lean on a claim that does not hold up. The real foundation is stronger than the legend: the right to resume self-government was reserved at the founding, it carries to every state equally, and Texans wrote it into their own constitution and never took it out.

First, the honest part about the "special deal"

You have probably heard that Texas, alone among the states, kept a written right to leave when it joined in 1845. That specific claim does not survive scrutiny, so we set it aside. What Texas actually kept, in the annexation agreement, was the right to divide into as many as four additional states, up to five total. That clause is real and on the record. But an exit clause is not. The annexation terms are simply silent on a right to leave. The good news is that the right to resume self-government never depended on a Texas-only clause in the first place. It rests on ground that belongs to Texas and every other state alike.

The Constitution does not forbid it, and silence is the answer

Start with the federal document. If a state leaving were prohibited, the Constitution would say so. Article I, Section 10 lists, in detail, what states may not do. Leaving the union is not on the list. Under the Tenth Amendment, every power not handed to Washington stays with the states and the people. No power to stop a state from leaving was ever delegated, so that decision was left exactly where it began, with the people of the state. In a system of enumerated powers, silence does not create a federal power out of thin air. It confirms the power stayed home.

Three states reserved the right to resume their powers, and Congress accepted it

When the Constitution was ratified, three states said in writing that they kept the right to take back the powers they were delegating. Virginia, ratifying on June 26, 1788, declared that the granted powers "may be resumed" by the people "whensoever the same shall be perverted to their injury or oppression." New York, on July 26, 1788, reserved that the powers of government "may be reassumed by the people, whensoever it shall become necessary to their happiness." Rhode Island said the same when it ratified in 1790. Congress seated all three without objection. That silent acceptance folded the reservation into the constitutional bargain the whole country joined.

The Equal Footing Doctrine carries that reservation to Texas

Here is why a reservation made by Virginia in 1788 belongs to Texas in 1845. Every state enters the union on an equal footing with the original states, with the same rights and powers, no more and no less. The Supreme Court said it directly in Coyle v. Smith (1911): this is a union of states "equal in power, dignity and authority." You cannot have an original group of states holding a reserved right to resume self-government while every state admitted later is permanently locked in. That would not be a union of equals. Whatever Virginia, New York, and Rhode Island reserved, Texas holds in equal measure.

Texas reserved the right in its own constitution, and still does

Whatever was reserved at the federal founding, Texans wrote the principle into their own fundamental law and have kept it there ever since. Article 1, Section 2 of the Texas Constitution declares that "all political power is inherent in the people" and that they have "at all times the inalienable right to alter, reform or abolish their government in such manner as they may think expedient." That language has appeared in every Texas constitution since the Republic in 1836. Texans reserved this right for themselves, in their own words, and never gave it up.

The bottom line

The story of a secret Texas-only escape clause is not the real argument, and it is not needed. The right to resume self-government was reserved at the founding, it belongs to Texas on an equal footing with every other state, and Texans wrote it into their own constitution in 1836 and have kept it there since. The reservation is real. It is just bigger than the legend.