User blog comment:Fegaxeyl/No US superpower - but how?/@comment-32656-20110801172704/@comment-257949-20110801223309

Perhaps a disastrous invasion of Japan? A worst-case scenario invasion, where they have to try repeatedly to successfully invade, and then get locked in a brutal war of attrition that sucks away their resources and attention. Obviously, for this to work the US wouldn't have access to nukes, so perhaps the Soviet Union got them first. If so, that would make the USSR even more of a superpower.

The one remaining question of this would be whether the USSR gets involved in the invasion of Japan or not.