An Unconstitutional Law is No Law
From Sixteenth American Jurisprudence, Second Edition, Section 177
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 statue 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 principles 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 Indeed, insofar as a statute runs counter to the fundamental law of the land, it is superseded thereby.
No one is bound to obey an unconstitutional law and no courts are bound to enforce it. -- Sixteenth American Jurisprudence, Second Edition, Section 177