Socialism

I heard this story from the Balkan trots and titoids many times; it continues with Tito sending a message to Stalin: If I attempt to assassinate you, it won't have a second time. They tell it more to disparage Stalin than to praise Tito, as I understand.

Now, I know Tito and Stalin have a clash of interest after WW2, but I don't think Stalin was the kind of man that would chase petty revenges.

In addition, I understand that this may be slightly off-topic, but could you also explain the reason that SFRY withdrew from the Eastern Bloc? According to ProleWiki, Tito was too ambitious about its control area in the Balkans and wanted to get closer to the USA, which obviously was not accepted well by Stalin. Is this the full story, or are there more to it?