Breaking up the 9th is long overdue, and in many respects was more needed than the split of the 5th circuit in 1981 that created the 11th. (Fun fact, Gerald Bard Tjoflat, was originally appointed to the 5th before the split and is the only remaining active judge in the 11th who was originally appointed to the 5th.) That said, the proposed split in Flake's bill is stupidly partisan. If the 9th is split, then the new 12th circuit should consist of Alaska, Washington, Oregon, Idaho, and Montana. However such a split wouldn't put a circuit court in Phoenix, which Flake's split probably would.