You may choose to delegate this responsibility to others, as Mayor Bloomberg and President Obama have, but your right to life is not inferior to theirs. It is equal. President Obama has no more right to live than you do. You are his equal from the standpoint of what your creator, and his creator, endowed both of you with. So we have established that you have the right to live, as does the President. And if the President has the right to defend his life with deadly force, and indeed the responsibility to do so, then, should it be necessary, so do you.
This debate should end right there. Up until all of these people in political office disband their police forces, their Secret Service details, throw down their own arms, armored cars, body armor and other defensive means of interdicting assault they have nothing -- not even a moral argument -- behind them in their demand that you disarm and become an intentional victim -- no matter who you are.