Most do, but in many cases their state Courts won't enforce those provisions. For example, the citizens of the state of Nebraska amended their state constitution, around 1986, IIRC, to provide
All persons are by nature free and independent, and have certain inherent and inalienable rights; among these are life, liberty, the pursuit of happiness, and the right to keep and bear arms for security or defense of self, family, home, and others, and for lawful common defense, hunting, recreational use, and all other lawful purposes, and such rights shall not be denied or infringed by the state or any subdivision thereof.
With the part in italics being the part added. Since then, the State Supreme Court has not overturned a single gun control law based on that provision. Even those which clearly infringe upon the right, declaring such laws to be Constitutional as "valid exercise of the State's police power in reasonable regulation of certain firearms" and "reasonable regulation by statute if the statute does not frustrate the guarantee of the constitutional provision."
IOW, they declared that provision, enacted by the people, to be null and void whenever the legislature intones the magic words "reasonable regulation". Hardly the actions of a republican form of government.
And you think that federal district court judges acting as state overseers will?
I mentioned earlier in the the thread that the Second Amendment has NEVER overturned a firearms restriction in this state. But when Diane Feinstein, then the mayor of San Francisco county, imposed a handgun ban and demanded that all such weapons be turned in, our state courts overturned her ban based on our state preemption laws.