Through Book III it has not happened...yet. Can't let too many future events out of the bag.
I will tell you this, in this fictional series, Dragn's Fury, the SHTF with both Red China and its allies, and a confederation of fundamental Islamic states, all combined in an unholy alliance against us...and it is no cake walk...it gets real dicey.
You write the books but all I gotta say is a ChiCom/Islamic Jihad team up is inevitable. May be run by rogue PLA elements what have you. The weapon is available (nukes). Only question is:
How can it be detonated on US soil with plausible deniability? What cut out will the ChiComs use? If I were ChiComs I would have a few prepositioned nukes on US soil with people who can maintain them. A low maintenance nuke.
Am reading "Icon" by Frederic Forsythe. Very good