Your phrasing of the question implied the law is Constitutional, was crafted and passed in a Constitutional manner, was declared so by the SCOTUS, or at least appears crystal clear why the law is Constitutional. Hence, I posed my question. Also, it is the duty of each citizen, to know and understand the law to the best of their ability, the opinion and any claims by SCOTUS notwithstanding. That duty includes adjudication of facts and claims that present themselves-to the best of their ability.
For instance... A ruling by SCOTUS declaring the campaign finance laws Constitutional does not make them so. The particulars of the law and how they stand versus the proscriptions and prohibitions of the Constitution does.
The idea that one needs to be granted some sort of authority by someone, or some entity to judge these matters is ridiculous. If that were true, then the idea of "the consent of the governed," was always w/o meaning and some other entity is, and has been in operation. There is also no point to education, since folks have no authority to make decisions anyway. Even classroom discussion of such topics and ideas would be pointless. Unless of course, education simply consists of what folks can and can't do along with the corresponding lists of sanctions and punishments.
It seems as though you live in an intellectual universe wherein your view of reality dominates. But, do you have the fortitude to intentionally violate a law which you believe is unconstitutional and suffer the consequences? If not, why not?