As the test for the new president, a group of Islamic nutjobs armed with AKs, ARs, handguns, and improvised explosives hijacks a gun-free zone. When the first of the first responders show up, they are met with car bombs. When the next wave shows up, they take aimed sniper fire from other locations.
After it's all boiled down, and what is left of the hostages and heroes are buried, and there's a national week of mourning and hand-wringing, Patriot Bill II is trotted out, and bans everything from slingshots up as "terrorist weapons."
Congratulations - you are now a terrorist.