Little further along those lines:
The city fighting we’d see in Europe would look like what we saw in
Sarajevo ten years ago. You know, ragtag bands of men with no uniforms,
stolen weapons, and a desire to kill anybody who looked Muslim (or on
the Muslim side, European).
Want to take the worst-case a little further? Both countries border
Germany, which might feel the very legitimate need to march in to
restore Ordnung. I think we all know what usually happens once the
Germans start goose-stepping through their smaller neighbors.
No, the result wouldn’t be World War III (or V?). But Europe could
very well become Bosnia on a continental scale, with all the
devastation, mass graves, and ethnic cleansing that implies. You can
bet, at best, there would be a whole lot of people put at gunpoint onto
refugee boats bound for North Africa and the Levant. Assuming, of
course, the Europeans win in such a scenario. If not, the poor refugees
would speak languages much like our own, and be bound for our own shores
– just like Will suggested.
Me, though, I’d put my money on the Europeans winning a war of mass, mechanized murder.
After all, they invented it.