Yes, I know, but the reality of it was, they weren’t.
Serbs should have been US allies. Tragic events placed in the Yalta Accord ended that.
And yes, I know it was a far leftist Serb that killed the Arch Duke leading to WWII.
That’s WWI, not WWII.
Gavrilo Princip was a “Yugoslav” nationalist, not a Serb nationalist. But he’s generally honored in Serbia just the same.