of a single State and
conducted within its limits exclusively is one which has been fully
recognized in this court, although it may not be always easy, where
the lines of these classes approach each other, to distinguish between
the one and the other."[33] He might have added some other comment to
the effect that this court will not definitely draw the line of
distinction between such classes of commerce since it desires to leave
adequate room for evasion, because it had been unusually easy to find
such a line in cases in which the rights of Negroes were concerned and
such definite interpretation might interfere with the rights of white
men. Justices Harlan and Bradley dissented on the grounds that the law
imposed a burden upon an interstate carrier in that he would be fined
if he did not attach an additional car for race discrimination, and
that the opinion was repugnant to the principles set forth in that of
_Hall_ v. _DeCuir_.

The United States Supreme Court finally reached the position of
following the decision of _Ex Parte Plessy_ which justified the
discrimination in railway cars on the grounds that it is not a badge
of slavery contrary to the Thirteenth Amendment. This decision, in
short, is: So long, at least, as the facilities or accommodations
provided are substantially equal, statutes providing separate cars for
the races do not abridge any privilege or immunity of citizens or
otherwise contravene the Fourteenth Amendment of the United States
Constitution. In such matters equality and not identity or community
of accommodations is the extreme test of conformity to the
requirements of the amendment. The regulation of domestic commerce is
as exclusively a State function as the regulation of interstate
commerce is a Federal function. The separate car law is an exercise of
police power in the interest of public order, peace and comfort. It is
a matter of legislative power and discretion with which Federal courts
cannot interfere.

In _Hennington_ v. _Georgia_,[34] it was later emphasized that it had
been held that legislative enactments of the States, passed under the
admitted police powers, and having a real relation to the domestic
peace, order, health, and safety of their people, but which by their
necessary operation, affect, to some extent, or for a limited time,
the conduct of commerce among the States, are yet not invalid by force
alone of the grant of power of Congress to regulate such commerce;
and,