I agree with old Roger... also as posted earlier on this topic all treaties must be approved by the Senate at a 2/3rds rule.
All treaties are also bound by the Constitution. Thanks to Heller, if the Senate does ratify the treary such a ban would fall.
And if the political process and legal process were to fail, and as a last resort, there is always the words of the Declaration of Ind. as to what our duty would be.