Well I'm not a legal eagle, but my impression is that they can really do just about anything they want. Superior courts can overrule them, pardons can be given, they can be removed but it is extraordinarily rare. Hell, whole courts can be abolished by Congress if they want (all courts but the Supreme Court are creations of and overseen by Congress). But nothing prevents him from exercising any area of discretion to any extreme he wishes whenever he wants.

Well I'm not a legal eagle, but my impression is that they can really do just about anything they want. Superior courts can overrule them, pardons can be given, they can be removed but it is extraordinarily rare. Hell, whole courts can be abolished by congress if they want (all courts but the Supreme Court are creations of and overseen by Congress). But nothing prevents him from exercising any area of discretion to any extreme he wishes whenever he wants.