I am talking about the US Constitution, not individual State Constitutions.How does a ballot measure that amends the constitution come under constitutional scrutiny? That is a non sequitur.
Yes, but the US Constitution limits the powers of the federal government (theoretically) and reserves powers not specifically granted to the federal government to the states or the people (10th Amendment). So, if a change is made to the state constitution by initiative with respect to a power not granted to the federal government by the US Constitution, e.g. health care, there is no federal restraint on such a change. Hence, the will of the majority applies, does it not?
The US constitution grants powers and also limits powers. 2A is an enumerated limitation, and therefore falls under the purview of the Federal government. It cannot be usurped by the States, no matter how hard they try, as evidenced by recent SCOTUS rulings.