It is emphatically the province and duty of the judicial department to say what the law is...If two laws conflict with each other, the courts must decide on the operation of each...This is of the very essence of judicial duty.

The constitution is either a superior paramount law, unchangeable by ordinary means, or it is on a level with ordinary legislative acts, alterable when the legislature shall please to alter it. It is emphatically the province and duty of the judicial department to say what the law is. This is the very essence of judicial duty.

Let the end be legitimate, let it be within the scope of the constitution, and all means which are appropriate, which are plainly adapted to that end, which are not prohibited, but consist with the letter and spirit of the constitution, are constitutional.

It is emphatically the province and duty of the Judicial Department to say what the law is.

Certainly all those who have framed written constitutions contemplate them as forming the fundamental and paramount law of the nation, and consequently the theory of every such government must be, that an act of the legislature, repugnant to the constitution, is void.

The law does not expect a man to be prepared to defend every act of his life which may be suddenly and without notice alleged against him.

The federal government is acknowledged by all to be one of enumerated powers. The principle, that it can exercise only the powers granted to it . . . is now universally admitted.