The Supreme Court of the United States (aka US Supreme Court) is the ultimate arbiter of constitutionality and makes the final decision to nullify (or void) a law.
Article V of the US Constitution states: The Congress, whenever two thirds of both Houses shall deem it necessary, shall propose Amendments to this Constitution, or, on the Application of the...
To create shared powers between the government and the states. This way depending on the economy or main resource, the states can set requirements such as; early driving licence so young people in a...
because other countries call their base of government the constitution and the answer to other contries constitutions is because that is what they decided to name it.