Online FEMA training presents to ME one of, if not the BEST argument for a very well-armed society.

The very nature of terrorist attacks underscores the importance of preventing such attacks from occurring. First, they typically occur with little or no warning. Second, they often involve multiple geographic areas. And finally, if multiple near-simultaneous terrorist attacks occur, they can be expected to exceed the capabilities of any one entity.

Preventing a terrorist attack requires a unified effort in a time-constrained environment. Therefore, to be prepared to prevent terrorism, the whole community must preemptively build and maintain the needed capabilities prior to a threat, and be ready to put them in action in a coordinated fashion once a threat is identified.
emphasis mine