plastic card, nicknamed the "biscuit". The United States has a two-man rule in place at nuclear launch facilities, and while only the president can order the release of nuclear weapons, the order must be verified by the secretary of defense to be an authentic order given by the president (there is a hierarchy of succession in the event the president is killed in an attack). This verification process is only to ensure that the order came from the actual president; the secretary of defense has no veto power and must comply with the president's order. Once all the codes have been verified, the president "may direct the use of nuclear weapons through an execute order via the Chairman of the Joint Chiefs of Staff to the combatant commanders, and, ultimately, to the forces in the field exercising direct control of the weapons." These orders are given and then re-verified for authenticity. It has been argued that the president has almost sole authority to initiate a nuclear attack because the Secretary of Defense is required to verify the order but cannot veto it. However, the president's authority as Commander-in-Chief is not unlimited; US law dictates that the attack must be lawful and that military officers are required to refuse to execute unlawful orders, such as those that violate the Laws of Armed Conflict. Therefore, the Chairman of the Joint Chiefs of Staff and other servicemembers in the chain of command must refuse to issue the execute order if such an order is unlawful. Several military officials, including General John Hyten, have testified to the US Congress that they would refuse to carry out an unlawful order for a nuclear strike. Yet if the Chairman of the Joint Chiefs of Staff were to refuse to issue the execute order as directed by the president, the president could reassign or fire the Chairman and appoint a replacement, including waiving the required credentials if all other qualified officers refused the appointment or if the president determined that it was in the national interest. In addition, off-the-shelf strike packages are pre-vetted by lawyers to confirm that they are legal and, thus, such a strike would be presumed to be a lawful order. Furthermore, military servicemembers have been reprimanded in the past for questioning US protocols for nuclear strike authority, notably Major Harold Hering, who was discharged from the Air Force in late 1973 for asking