North Korea might be able to fire off a nuke via scud or other delivery system, but I'd have to imagine the US and allies know exactly where these locations are. To avoid any type of nuclear response, they have to attack those locations first. They aren't Russia where you take out 3 launch pads and then they fire from the other 497. A well planned strike on the launch pads could cripple them in minutes and avoid any allied country being attacked.