Now logically, if we can draw the line at nuclear weapons due to their level of impact, can we not draw the same line at any level for the same reason?
Logically, no. If nuclear weapons are an
exception to the rule based on extraordinary circumstances, then that "exception" status becomes degraded as more and more exceptions are created. In order to preserve the circumstances that justify banning nuclear weapons as being
extraordinary such as to warrant an exception, then all other exceptions must be, at the least, highly restricted to only those things that are also extraordinary.
Or, to say it more plainly.....
The "nuclear weapons" argument in regards to gun control is not logical in the first place. It is fallacy of accident, i.e. a case of finding an exception to a general rule, and then attempting to create or permit the exceptional case as the new general rule. Such arguments can be seen to be invalid easily enough based on their obvious nature of failing to take the exceptional circumstances into account. For example:
Bob: Children should mind their parents
George: No, they should resist them and run away like Tracy did after being beaten and abused by her father.
Bob: You're right. Children should resist their parents and run away. [note lack of qualifer regarding Tracy's exceptional circumstances]
Aside from this, fallacy of accident arguments also have a circular tendency as well, which further requires their rejection. Taking the nuclear weapons example, the reason nuclear weapons are okay to ban despite the second amendment is because
they are so exceptional that the constitute and justify an exception from the normal rule. The permissibility of banning nuclear weapons is based on the fact that they are
exceptional, and thus can be treated differently. However, if they way nuclear weapons are treated
becomes the new standard approach to all treatment of weapons, then the first class is no longer entitled to be banned. Without being the exception, the original rules apply. And so it happens that invoking an exception to a general rule as grounds to change a general rule becomes question begging, because the justification proposed
already rests on the presumption that conclusion being supported is already a valid conclusion.