Obviously Spain would prevail over those traitors to the Catholic Christianity ! Nobody expects the Spanish Inquisition...
P.S I would prove of the best reason why Spain should be the 3rd faction, and it's very simple: We have (and are) the best faction to provide the best feeling when you use the taunt. Yep, that's it, none existing faction has such variety over insults and offensive words and we use it daily in all the situations.
Imagine the situation: 200 players, half in spanish team and all of them using "Insult" voice command... your hear would have an orgasm.
Check mate, Prussianfanboys.