See, that's what I mean. You're afraid of what might happen. 9/11 was an intelligence failure at the top levels. Since 9/11, every single major terrorism attack has been thwarted. Every single one. You can't live your life in fear.
Yes, a nuclear or biological attack would be terrible, and atrocious. But it doesn't have to crush the American economy, either. What actually hurt the US economy? It wasn't cleaning up the damage or rebuilding the Twin Towers or the Pentagon. It was the sudden trade barriers the USA threw up. The addition of the unnecessary TSA to everything travel-related. Tripling security on all possible things that could happen, when all that really needed to happen was the people at the top needed to pay more attention.