Sons of the Little Sahara
Oklahoma is the marcher land between Texas, and the horrors of the High Plains. About the only good thing that you can say about the state now is at least it rains more often — but even then, flooding is a constant problem, and it’s not smart to drink Serpent-tainted groundwater for too long. So Texas moved the population of the state south, placed garrisons along Route 66 using what troops it could spare, and generally contents itself with maintaining a watchful peace on its northern border. The Texan state government has no interest in expanding further in that region, and certainly cannot spare enough resources to maintain even the pretense of the rule of law, north of the Double-Six. Indeed, some Texans argue that the border should be even further south; if it wasn’t for the fact that Texan control over Los Alamos might be endangered by the loss of Route 66, those arguments might be better heeded.
Still, not everybody in Oklahoma left. In particular, there’s a community called ‘Little Sahara,’ so named because they’re north of the Double-Six and operate out of actual natrual sand dunes (just south of what used to be Waynoka). These dunes were deemed pretty useless, back before the skies alternated between astringent rain and stinging snow. Now the dunes are a remarkably reliable source of clean water: with the right brute-force approach the tainted water gets drained through the sand, leaving the Serpent-taint behind. The inhabitants still have to be careful of overly-tainted sand, but that can be managed well enough. The important thing is that there’s water. Clean water.
Which means that every raider gang or death cult in Kansas knows what their dream target is. Little Sahara would get more raiders if more raiders had reliable amounts of gasoline; as it is, they can expect at least two, three motorized raids a year. Typically, the raiders attack using stripped-down cars and cycles converted to ethanol, relying on speed and surprise to target the water collection points, then retreat before the defenders can react. It works just often enough to keep the raiders from taking the next obvious step of combining their forces, conquering Little Sahara outright, then having the survivors of the assault slaughter each other en masse while the broken pipes gurgle out their last precious drops of clean water onto an uncaring, sodden wasteland. There’s a vested interest in the status quo, in other words. On every side.
Also note: bullets and other ammo get rarer every year, north of the Double-Six. Little Sahara could probably afford to keep themselves stocked, but they just don’t get all that many civilized traders, that far north. Which means that a caravan planning to trade bullets for cash in the Poisoned Lands won’t have to go past Little Sahara to make a tidy profit. Or to get into trouble, when it gets out among the raiders that the settlement won’t be needing to make every shot count in the next raid. That might be enough to finally spark a war of conquest and despoiling, right there.