I think it is an interesting subject too. Hopefully your interest in the subject is motivated by concern for the country you love, like me.
It's all true. When the plane hit the Pentagon, I was a bit worried about my dad, but knew it was unlikely he would be there that day.
Whether terrorism or an accident, the Baltimore bridge collapse shows how vulnerable we are. There would have been hundreds killed if they had not managed to shut off traffic two minutes before the ship hit it, and it doesn't take a suitcase nuke.
I think a credible threat comes from open borders. There could be many squads of bad people entering. Individually, or collectively, they could do great harm.
Regards,
Jim