Quote from Mugler v. Kansas,
The courts are not bound by mere forms, nor are they to be misled by mere pretences. They are at liberty — indeed, are under a solemn duty — to look at the substance of things, whenever they enter upon the inquiry whether the legislature has transcended the limits of its authority. If therefore, a statute purporting to have been enacted to protect the public health, the public morals, or the public safety, has no real or substantial relation to those objects, or is a palpable invasion of rights secured by the fundamental law, it is the duty of the courts to so adjudge, and thereby give effect to the Constitution.
Mugler v. Kansas (more quotes by Mugler v. Kansas or books by/about Mugler v. Kansas)
Mugler v. Kansas, 123 U.S. 623, 661.
Judiciary, Law, Integrity, Health, Morality, Safety, Rights, Law, Constitution