American citizens can also be terrorists. When a politician is willing to put on a "Congress on your Corner" public event in a supermarket in the middle of her political district, and is shot for her efforts, the person who did the shooting is a terrorist.
If it was a man who did the shooting, I find it even more troubling. If the shooter has a demonic axe to grind, do it against your own sex, coward. You can read more here.
Donna Brazile chimed in with the most obnoxious message one could imagine, it actually sounded like Brazile was describing her own despicable behavior in 2008 when she said "The increasing levels of incivility, intolerance and a political climate that favors those who threatens, bully others must end. I am so sad".
That is pretty much what Brazile did in 2008, at one point actually threatening to riot in the streets if Barack Obama did not win the democratic nomination.