Liberal in America usually consider the Nation to be the State. They say America is the Constitution, and didn't exist before 1789. Or, in practice, that America is the federal bureaucracy. "What is the Nation?" is a hard question, but that's the wrong answer. If the Constitution were adopted by Armenia, that wouldn't make Armenia identical to America. The Nation is some amalgam of people, culture, location, language, history, and State. Just like The Church, or any other noun describing a group of people.