The answer: "Carry Permits" for those willing and with training.
The results:
Scene I Act I: Terrorist enters shopping mall. He cries "Allah Akbar" as he tries to detonate explosives.
Scene I Act II: Twelve nearby armed Americans draw their firearms and drill the bastard with seventy rounds of hot lead.
Scene II: Epilog. Body deposited into a local cesspool. Another sub-human monster on his way to hell.
That's my cheerful outlook for now. Good night!