The principle that holds that the powers of government should be limited and embodied in a basic written law is referred to as

The principle that holds that the powers of government should be limited and embodied in a basic written law is referred to as constitutionalism.
This means that the government has to adhere to the Constitution, which is the utmost and most important law in a country. Anything that doesn't somehow align with the Constitution will be considered illegal, so obviously the government has to follow its rules.