Try thinking beyond the actual words that are used and try to understand the meaning and implication of those words. That section with Article I Section 9 and the 10th amendment clearly places the control of the borders in the realm, jurisdiction and authority of the Federal Government. That includes any foreign invasion by any number of people that are not citizens of this country. It does not have to be a foreign nation sponsored army, it does not need to even be an army or even sponsored by anyone. It can be just a large "influx" of foreign nationals. And you seem to have nothing to say about the rest of what I posted.
What evidence is there that a NICS check does anything at all (other than slow down a legitimate purchase)? How did the whole system work prior to '68 when you could write a check and mail it to a company, then have the firearm show up on your doorstep a few weeks later?
Try to wrap your mind around this concept: You can not prove a negative! You can not prove that you did not commit a crime in the past. All the NICS check is, is a huge (and significantly flawed) data base (several actually) that contains lists of PEOPLE that THEY BELIEVE MAY commit a crime based on selected criteria. Many of which are not violent and/or should not preclude firearm ownership. Just remember "Three Felonies a Day", and the fact that it is "felony" you loose.
Non Sequitur.