Sixteenth American Jurisprudence, Second Edition, Section 177:
"The general misconception is that any statute passed by legislators bearing the appearance of law constitutes the law of the land. The U.S. Constitution is the Supreme Law of the Land, and any statue, to be valid, must be in agreement. It is impossible for both the Constitution and a law violating it to be valid; one must prevail.
This is succinctly stated as follows: The general rule is that an unconstitutional statute, though having the form and name of law, is in reality no law, but is wholly void, and ineffective for any purpose; since unconstitutionality dates from the time of its enactment, and not merely from the date of the decision so branding it. An unconstitutional law, in legal contemplation, is as inoperative as if it had never been passed. Such a statute leaves the question that it purports to settle just as it would be had the statute not been enacted."
"Since an unconstitutional law is void, the general principals follow that it imposes no duties, confers no rights, creates no office, bestows no power or authority on anyone, affords no protection, and justifies no acts performed under it.... A void act cannot be legally consistent with a valid one. An unconstitutional law cannot operate to supersede any existing valid law. Indeed, insofar as a statute runs counter to the fundamental law of the land, it superseded thereby. No one is bound to obey an unconstitutional law and no courts are bound to enforce it."
MARBURY v. MADISON, 5 U.S. 137 (1803):
Why otherwise does it direct the judges to take an oath to support it? This oath certainly applies, in an especial manner, to their conduct in their official character. How immoral to impose it on them, if they were to be used as the instruments, and the knowing instruments, for violating what they swear to support!
The oath of office, too, imposed by the legislature, is completely demonstrative of the legislative opinion on this subject. It is in these words: 'I do solemnly swear that I will administer justice without respect to persons, and do equal right to the poor and to the rich; and that I will faithfully and impartially discharge all the duties incumbent on me as according to the best of my abilities and understanding, agreeably to the constitution and laws of the United States.'
Why does a judge swear to discharge his duties agreeably to the constitution of the United States, if that constitution forms no rule for his government? if it is closed upon him and cannot be inspected by him.
If such be the real state of things, this is worse than solemn mockery. To prescribe, or to take this oath, becomes equally a crime.
It is also not entirely unworthy of observation, that in declaring what shall be the supreme law of the land, the constitution itself is first mentioned; and not the laws of the United States generally, but those only which shall be made in pursuance of the constitution, have that rank.
Thus, the particular phraseology of the constitution of the United States confirms and strengthens the principle, supposed to be essential to all written constitutions, that a law repugnant to the constitution is void, and that courts, as well as other departments, are bound by that instrument.