Imperial immunity

An American Federal court has thrown out a lawsuit against Caterpillar, Inc by the family of Rachel Corrie over Ms. Corrie's death beneath an armoured bulldozer manufactured by the company and operated by Israeli security forces because, as the equipment was primarily paid for by the American government under military aid to Israel the court would be intruding on Executive Branch powers to conduct foreign policy. The court argued that they could not hear the case, which alleged that the company had aided and abetted "war crimes and other serious human rights violations" through the provision of equipment that they knew would be used for illegal activities, "without implicitly questioning, and even condemning, United States foreign policy towards Israel".

Does this tell us that the Executive Branch is immune from any investigation of violations of American or international law in the conduct of foreign policy by any American court? Good thing the International Criminal Court exists! Wait a minute. We never signed up for that did we? I think I now understad why not.