[Flyndaran]

People love to idealize victims and give them far more leniency than they would otherwise get. Look at how much Bush Jr. and New York city's mayor had to do to squander the adulation from 9/11.
Getting nuked would allow soviet influences of all sorts to spread with less impedance even if their economic power was greatly reduced.

Edit: Not to throw out my political opinions, but Bush Jr.'s policies would not have had anywhere near the lack of opposition if playing the victim wasn't an option.