Law enforcement need not wait for someone to "commit a crime" with a bomb; just making or having one is itself crime enough to send them to prison if caught. Since the Oklahoma City bombing mass quantities of fertilizer DO require permits, specifically to prevent someone repeating Timothy McVeighs actions. How many have? The only one I know of is Breivik, who did it halfway around the world and had to create a fake agricultural business to get the fertilizer.

I am not panicking at all; I am simply saying that if we do not allow universal access to bombs, cars and tons of fertilizer on demand, no questions asked, we should not do so with guns. If you want panic, talk to my relatives who insist there is "already SO MUCH gun control" nothing further is possible except confiscating all of them. Talk to the people who think a UN treaty to ban SOME IMPORTED weapons equals gun confiscation. Talk to the gun rights advocates who insist any and all gun control equals confiscating all guns. Bring a dictionary for them; you will surely need it.