(in a southernly drawl) we'll just in-vade 'm!
The time table for the war appears to be within the next 3 months, which does surprise me a bit (I figured for an April-September war for the rating^w^w^wreviews and Presidental election boost).
But, given the country, I seem to recall that a Winter strike is called for (better weather for the troops) and it frees the US up enough to more aggressively ..er...deal with NK. (Which could be on that aforementioned time-table).
As for the justification, I wouldn't worry about it. If the CIA agents are doing their job, something will be discovered (and presented) that will show the "our worse fears are confirmed". (And you thought newspapers could cause wars.)