If you can prove it you would need to sue the hospital.
The US constitution is the supreme law of the land. Following that, Federal law is supreme (or controlling).
The Supremacy Clause. Someone else said: Preemption Clause of the Constitution makes the federal law trump state law but it does not necessarily render the state law invalid unless following state law would violate the federal law.
As will all legal issues, your answer may vary depending on the state where you are renting. In general though, as long as the landlord notifies the tenant and the tenant agrees to it, then a background check would be legal.
State Police
deciding the constitutionality of a state law that requires drivers to wear seatbelts
Very well. They are audited by the state and independent observers who come to the school/district to talk to teachers and to document that they are following state/federal educational law.
State Law
The US Constitution takes priority over a common-law decision in one state because it is the supreme law of the land. Any state law or decision that is in conflict with the US Constitution is considered unconstitutional and therefore invalid. Federal law, including the Constitution, supersedes state law in such cases to ensure consistency and adherence to constitutional principles.
Constitution
That really depends on what state you're in. Laws vary from state to state concerning family matters. I would look into your individual state's law for a more accurate answer.
"One must remember that a man lives best when he is true to himself." - Antigone speaking about the conflict between following divine law and man-made law.
A state lemon law is a law created to protect consumers in the instance of purchasing a "lemon" vehicle. This would be a vehicle that is defective. Different states have different laws about what should happen in those instances. For example, the following talks about the lemon law in Arizona and how it works: <a href="http://amazingchild.hubpages.com/hub/az_used_car_lemon_law">AZ Used Car Lemon Law.</a>