I'm sympathetic to the gun rights cause, but Rudy Giuliani's rationale for embracing it really doesn't make much sense:
I also think there have been subsequent intervening events, September 11th, which cast somewhat of a different light on the Second Amendment and Second Amendment rights. Doesn't change the fundamental rights, but maybe it highlights the necessity for them more.
The trouble here, of course, is that Giuliani personally and the GOP more generally is deeply invested in the idea that 9/11 means we need more restrictions on individual liberties, not more rights. More broadly, this is especially odd because I think Giuliani had already been using a different, more plausible rationale for flip-flopping about gaining a broader perspective when he started to take a wider view of the country beyond the crime-plagued early nineties New York that was the initial impetus for his views.