First there is its federal constitution, with its balance between powers held at State and local level and those held centrally. Federal law is the same everywhere and overrides State law. And it is watched over by a central Supreme Court of appointed but independent judges. Second , decisions on law and policy are taken by democratic means, at whatever the level. And legislative action requires the interaction of an Administration and two legislative bodies, of different constitution and with different roles.
Power is shared.
Tyranny is impossible. Third, this is a market economy, with the Interstate Commerce Clause ensuring that a company can do business throughout the 50 States, although you know better than I that local rules also remain. And the federal commercial law governing the way you operate ensures that you can defend your constitutional rights also in the business domain, up to and including the protection of the Supreme Court. Fourth, you have a single currency, the mighty dollar, with which you can pay throughout the land, and in much of the rest of the world as well. Fifth you have the armed forces, which came to our help in the past, stood shoulder to shoulder with us during the long, dark days of the Cold War, and remain in Europe within the NATO alliance, which is still a major force for peace in the world.