[Flyndaran]

It doesn't have to be a worst case Yellowstone scenario during the Cuban Missile crisis to induce a Lucifer. Just big enough to make Kruschev think it's a good time to launch a preemptive strike. Being wrong or even slightly off may allow the U.S. to launch some counter attack, and/or third parties to take the distraction as cause to start their own wars.
Realistic crap-sack global conflict but lacking united sides like in the world wars.