Reformed Covenanter
Cancelled Commissioner
Judge Moore is not disobeying legitimate civil authority, because he is a legitimate civil authority, being a civil magistrate he is one of "the powers that be" or "the governing authorities" who has a right to resist higher levels of civil authority when they step-outside their God-appointed role.
In Romans 13, Paul is not writing the state a blank check, but outlining what its God-appointed role is.
Romans 13:1: "Let every soul be subject to governing authorities."
Moore was subject to (and should have obeyed) the rule of the other 8 supreme court justices, who in this case were his "governing authority." I agree that if they had abused their power or had caused Moore to sin by following their order, he would have the right to resist (as Calvin would no doubt agree). But they didn't abuse their power, and they didn't cause him to sin. Whether or not you agree with his stand on the monument, I fail to see how he had the right to disobey the legal authority in this situation.
But he is one of the governing authorities, so he has the right to resist their tyranny as they were stepping outside their God-appointed role, and he, as a lawful lesser magistrate, was resisting them.