Shadows of North America has some decent CAS info, and there's the usual couple-page blurb in The Sixth World Almanac. There have been long-simmering hostilities (troops near the border, heavily guarded checkpoints, lots of angry glaring) between the CAS and UCAS, but with the ongoing pressure from Aztlan to the south, the CAS hasn't gone out of its way to get into an open "hot" conflict with the Yankees, or anything.