n a proper police motive is disclosed in the
statute, it is the _best_ method of effecting the result. This, I
think, is a clear statement of the principle of our court decisions.
If, upon the face of the statute, the court can see no possible
relation to the public health or safety, or, possibly, general
welfare, it will hold the law null in so far as it invades either
property or liberty rights because not under the police power. If, on
the other hand, they can see _some_ relation to the public health,
safety, or general welfare, even though they do not think it the best
method of bringing about the desired result, they will not presume to
run counter to legislative opinion. Of the expediency of the statute,
the legislature must be and is the final judge.

With us the police power is exercised largely for moral reasons. That
is to say, the great instances of its extension have been connected
with moral or sanitary reform. No doubt the police power may broaden
with advancing civilization and more complex appliances and possibly
greater medical knowledge and social solidarity. No doubt purposes
which were once lawful may be unlawful, and property devoted to them
thus be destroyed by a change in the law. Mr. Justice Brewer, of
our Supreme Court, holding the contrary view, was overruled by the
majority, and that decision is final.[1] Not only we, but a State, may
not even make a contract which shall be immune from future extension
of the police power, the Dartmouth College case notwithstanding. For
instance, the State of Massachusetts in 1827 granted a perpetual
franchise to a corporation to make beer. It was allowed, forty years
later, to pass a law that no corporation should make beer, and the
brewery became valueless. The State of Minnesota granted a perpetual
franchise to a railroad to fix its own fares. Twenty years later
it took away that right, thereby, as claimed, making the railroad
property valueless; the railroad had no remedy. A man in Connecticut
had barrels of whiskey in a cellar for many years, but the State was
allowed to pass a law prohibiting its sale; which, of course, had he
been a teetotaler, would have deprived that property of all value, and
in any case, of all exchange value. A man in Iowa owns one glass of
whiskey for several years, and then a law is passed forbidding him to
sell it; the law is valid. A youth in Nebraska buys tobacco and paper
and rolls a cigarette. The State afterward passes a la