Courts below a circuit also pay attention to other circuits. If there is no ruling in their circuit a judge will cite the other circuit(s) in their ruling. (they can go either way, but they make it clear they considered it and why they think the other circuits are right/wrong) Rarely a judge will cite a different circuit and go against their own circuit, but this is very rare (either the judge will point out substantial differences from the case the circuit ruled on and those differences mean the ruling shouldn't apply - this is likely to be appealed and if the higher court remains firm it is a black mark on the lower judge; or the judge will point out the law changed and so the ruling isn't valid anymore unless the higher court rules it unconstitutional which of course then lower judge cannot do)