I'm worried about the government response more.
I doubt you'll see Congressmen and Congresswomen going to campaign stops without extra security for awhile now at the very least. I doubt any sort of laws will be passed on a larger scale.
What kind of laws could you pass? "It is henceforth illegal to shoot Congressmembers"? I think we already have that one. Hell, I'm pretty sure this is even a federal crime, because she's a federal employee who was shot while carrying out her job as a federal employee, much the same as that postal worker who was shot while delivering mail a couple years back.