Ignoring the unintentional implication of "Slavs aren't white", I'd suggest that both Russia and China exist in some form, even if it's fragmented. If anything, Slavs tend toward creating independent countries and claiming that they're completely different nations some decades later. European Union most probably wouldn't exist in your world, but knowing Germans, they'd most likely become a dominant European power (they just don't know when to quit). In such a war that hit the planet, I'm pretty sure that the smallest and the least important countries would be no more. So, basically, business as usual in Africa, Balkan Peninsula is a giant crater, Middle East a nuclear wasteland instead of a desert one and somebody accidentally vapourised both Koreas. Also, there's S.T.A.L.K.E.R.: Tears of Fukushima in Japan.

So the second reason. Gotcha. I'm asking since I have an idea for a character being a brain stuck in a miniaturised combat mech.