What's good for the goose is good for the gander... Although the above would be the time-traveler version. Try explaining "nuclear" to somebody in the 1700s and expecting it to stick to the 1900s.
Modernly, I probably would go with "The right of the people to keep and bear arms shall not be infringed. Laws limiting weapons in any way are prohibited, including but not limited to background checks, registration lists, and places where they can be carried. All governments, foreign and domestic, should be afraid of the armed populous. Nuclear weapons of any size may be regulated and prohibited. Biological and chemical weapons of over (researched volume or weight) may be regulated and prohibited. "
In a civil war, you would want to be able to at least shoot down the aircraft so they can't deploy the three banned weapon classes.