If Springdale were to ally itself with a city, a large proportion of whose government and skilled citizenry attacked it's citizens, Springdale would be a stupid city. If Springdale were to ally itself with a city, whose population did not attack its citizens, or allow it's citizens to run rampant through it's streets, Springdale would be a sane city. The fact that Springdale's current allies are good, surely points to a couple of things. It's allies respect it as a City in it's own right and the citizens of both cities do not attack Springdalians out of basic respect for their fellow man.
Perchance if the self professed \"evil\" city were to approach this triumvirate of allies with peace, rather than a horde of ravening (fill in with name of random nasty) it may gain a pleasant surprise. If it's hostile stance towards the rest of the pe oples in the land continues to escalate, it may have noone left to turn to when the time comes.