-- in the end it pretty much comes down to this: If you want the protections guaranteed in the United States under the Constitution, you probably shouldn't go around renouncing your allegiance to it or making war on it.
But in the end it pretty much comes down to this: If you want to claim that the States had not seceded, and were still citizens of the US, then their Constitutional rights are guaranteed.
Your state government has no power to force an individual to renounce US citizenship.
All persons/civilians in the seceding States remained citizens of the US unless they personally renounced citizenship or aided the rebellion.
By seceding & making war, those in actual rebellion had forfeited their rights to be treated as citizens. As belligerents, their rights to life, liberty or property could be lost.
It seems we have a Tory in our midst. At that time a person possessed American citizenship by virtue of state citizenship. If a person chose to remain a citizen of the US, all they had to do was move to a state remaining in the union. No one forced them to stay.
Secession did not mean war - is simply meant that the people of that state chose to exercise their powers as described under the Declaration of Independence, and guaranteed by the Tenth Amendment of the federal Constitution. The seceded states did not send armies to Washington to depose Lincoln and overthrow the federal government. As belligerents, their rights are still God-given:
We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness. That to secure these rights, Governments are instituted among Men, deriving their just Powers from the consent of the governed, -- That whenever any Form of Government becomes destructive of these ends, it is the Right of the People to alter or to abolish it, and to institute new Government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Safety and Happiness.Lincoln waging war against the seceding states was a war against the Declaration.