Folks always try to derail the DM, chief. It encourages them to design better railroads in the future. 
Well, the hypothetical seems designed to force us to say we’d launch. Saying “don’t fight the hypothetical” seems to be trying to limit the discussion to answers you want.
One reason I don’t really like this sort of hypothetical is that in the real world, exactly this sort of hypothetical has been used disingenuously to trick people into accepting actions they would otherwise have rejected. Remember all the torture proponents endlessly repeating the “ticking time bomb” hypothetical? “If you KNEW the bomb was going to go off and you KNEW the captive could tell us when and where…” But in the real world, you NEVER know.
That makes it hard for me to respond to the hypothetical. Too much recent taint from evil, manipulative people trying to mislead.
Taking the OP at face value – sure, ultimately self-defense is justified. Pre-emptive self-defense is a murkier question by far. What if a similarly “credible” report came across your desk but the country in question was a surprise…say, Canada?
NK has a history of tunnelling and fortifying. In practice, it might be very difficult to destroy with confidence any missiles whose exact location is unknown…unless we use so much overkill we permanently wreck South Korea and surrounding countries
NOT pulling the trigger got us through the Cold War. I think it would be very hard to pull the trigger preemptively, there are a lot of compelling reasons not to do so.
Agreed.
Which, FTR, was exactly what I was obliquely saying in post #56. For any politically realistic evaluation of such intel using trolley logic, the US launches basically for the heck of it on a whim or on a the barest hint of a rumor.
And that’s clearly insane. Which clearly shows that the decision logic used to arrive at the insane decision is itself flawed or even insane.
I was hoping to ignite some righteous indignation, or at least some comment, by the OP or Richard Parker or anybody. The OP implicitly invited trolley logic and RP made it explicit.
Since none’s been forthcoming it seems folks have lost interest in the thread.