I don't quite see how any single country, in this day and age, could possibly contemplate even trying to being something in the sense of a war, that would drag in multiple countries, and especially the most economically and militarily developed countires in the world.
It would be absolutely pointless to go to war, or invade a country or attack a country using Nuclear weaponry, as you probably wouldn't survive for much longer afterwards as you're attacked by multiple countries with far superior armies and tactics than your own.
If ever there is a WorldWar 3 though, I'd imagine it would start with one hell of a bang.