EVEN IF...
...The UN has no say in what we, as americans do, If the UN were to pass the ban, that would become a VERY POWERFUL tool for the brady bunch and other nogunners to use convincing the sheeple majority and getting their way.
...Some americans resist the collection of guns by US or UN forces, these people will quikly be labeled as "terrorist". It would be better for everyone if a stop was put on this "just in case" rather than let it evolve into a situation that puts our families in danger.
If the UN does pass the ban, you can rest assured that our rights will be gone in a decade or two. The politicians aren't going to resist forever, sooner or later it will become a matter of "comply or be forced to comply" and our country will bow down to the UN. After all, we don't like going to war with guys who are as well trained and equipped as ourselves.
Try to see this for what it is, A POWERFUL FOREIGN POWER WANTING TO RESTRICT OUR COUNTRIES ARMED POPULATION.