Manhattan Project scientists stolen by USSR when they try to get out of Germany. USSR gets atom bomb first (in 1943-44), US doesn't get it at all until it's too late.
When WWII (European front) ends, and the US troops aren't going to get out of Japan that (as the Soviets think) rightfully belongs to USSR, the Soviets proceed to declare war on the US and nuke the triangular heck out of them.
After that, the Soviets, without any real resistance left, proceed to convert the rest of the world to communism by 1960 and create a world-wide USSR by 1980.
I'm not going to detail what happened later on (not least because my imagination fails me there); let's just say that by 2011, freedom is slavery, ignorance is strength, war would've been peace if there was any of either left, and whatever was called "religion" is all classified as thoughtcrime. (Also doubleplusungood.)

(Yes, I realize that's all ASB. That's about the only way I could imagine to attain the OP condition with a post-1900 POD that doesn't significantly involve at least one of Edison, Tesla, and Robert Wood.

)