[Old Sarge]

What would happen if roving gunmen infiltrated U.S. cities and started shooting?

Absolutely nothing - to the shooters.

The Sheep will cry in great voices to the One (piss be upon him), and demand that those nasty guns be taken away.

And The One (his name be pissed) will spread His hands, and all shall be made good.

Meanwhile, the funerals will be held...

[aruanan]

What would happen if roving gunmen infiltrated U.S. cities and started shooting?

You'd have various news reports about increases in gang warfare having to do with illegal drugs.