How would extradition between Texas and the U.S. work?

The same way it works between the United States and every other friendly neighbor: through an extradition treaty negotiated between the two governments. Extradition between sovereign nations is one of the most well-worn paths in international law, and an independent Texas would simply join the dozens of countries that already have such an agreement with the United States.

Extradition between countries is routine and well-established

Countries that border or trade with each other almost always have an extradition treaty, and the United States has them with a long list of nations. These agreements set out which offenses are extraditable, what evidence the requesting country must show, and what protections the person sought is entitled to. There is nothing exotic about it. An independent Texas and the United States, as close neighbors with deep ties and a shared interest in not becoming havens for each other's fugitives, would have every reason to conclude exactly this kind of treaty, and the template for it already exists many times over.

The core rule protects people on both sides

The foundation of modern extradition is a principle called dual criminality: a person can be extradited only for conduct that is a crime in both countries. A country does not hand someone over to be punished for something that is perfectly legal at home. Treaties also typically require that the offense be serious, usually punishable by at least a year in prison, and that the requesting side actually show a real case. These are protections, not loopholes. They mean a Texas-U.S. extradition treaty would surrender genuine fugitives from serious crimes while shielding people from being shipped across the border over conduct that is lawful where they live.

Texas already does this inside the union, and it scales up cleanly

Texas is no stranger to handing fugitives across a line. Right now, when someone commits a crime in another state and flees to Texas, Texas returns them through interstate rendition, and Texas reaches into other states for fugitives the same way. The machinery, the warrants, the legal process, the law-enforcement coordination, already exists and runs constantly. Independence converts that state-to-state process into a nation-to-nation one. The legal label changes from interstate rendition to international extradition. The practical work, locating a fugitive and lawfully transferring them to face justice, is something Texas authorities already do.

A practical agreement serves both sides

Neither Texas nor the United States benefits from becoming a bolt-hole for the other's criminals. That shared interest is precisely why extradition treaties get signed. A fugitive from a Texas court should not be able to escape justice by crossing into the United States, and vice versa. A clean extradition treaty closes that gap in both directions, which is why this is among the easier pieces of the transition to predict: it is in everyone's interest, and the world does it as a matter of course.

Rights are built into the process

Extradition under a treaty is not a snatch-and-grab. It runs through courts and includes safeguards: a person can contest the request, the dual-criminality rule must be satisfied, and customary protections apply. An independent Texas, operating under its own Bill of Rights with its guarantees of due process, would conduct extradition the way rule-of-law nations do, through legal channels with the person's rights intact.

The bottom line

Extradition between Texas and the United States would run through a standard extradition treaty, built on the dual-criminality principle that protects people on both sides. Texas already returns fugitives across state lines every day; independence turns that into the same nation-to-nation process the United States already shares with dozens of countries. Genuine fugitives face justice; lawful conduct is protected.