Dog got busted
The extradition treaty is just an agreement between two sovereign governments, to return one another's nationals. But for any treaty to have force, it must be ratified in the domestic law that governs the actual territory of each country. So both Mexico and USA have to pass their own extradition laws that satisfy the terms of the treaty.
So when America does want an American person back to face trial, Mexico is then required by its own law to extradite that person to face justice in the United States. Not because they have a treaty with the United States, but because they ratified that treaty with a Mexican law that they are themselves required to carry out. And they will do so because they value their relations with the United States and their status as a nation of laws.



