If we yielded to this contention of the plaintiff in error, we should
render the sections in valid by giving them a strained construction,
which would make them antagonistic to the law of congress. We cannot
attribute to the legislature, unless compelled to do so by its plain
words, a purpose to pass an act in conflict with an act of congress on a
subject over which congress is given authority by the constitution of
the United States. We are, therefore, of opinion that, fairly construed,
the sections of the Military Code referred to do not conflict with the
laws of congress on the subject of the militia.
--Presser v. Illinois, 116 U.S. 252 (1886)
