Joseph McKenna, Erie Railroad Company v. Williams…
“ Each instance of asserted conflict must be determined by itself, and it has been said many times that each act of legislation has the support of the presumption that it is an exercise in the interest of the public. The burden is on him who attacks the legislation, and it is not sustained by declaring a liberty of contract. It can only be sustained by demonstrating that it conflicts with some constitutional restraint, or that the public welfare is not subserved by the legislation. ”
