I doubt two or more Eurpopean states will go to war with each other a’ la 1939. What is likely to happen is the conjunction of the two primary political forces-(socialism and Third World invaders)-leading to internal chaos. It will be like the recent events in London only the action will not stop for several years running. The revolutionaries will be supplied by weapons provided by Islamic States, the fervor will come from race and socialism.
Then the fun begins.