Can President Trump shoot off the nukes whenever he wants to, even for no reason?

Question

According to a recent editorial in Scientific American(March 1,2017 "Take the Nukes off a Short Fuse"), the president of the United States can order missiles to be shot off without anyone else concurring. Also, are military personnel legally bound to obey this? Maybe a soldier could legally disobey such an order on the grounds that it was an illegal order or that it "shocked the conscience?"

Answer 1

The Commander-in-chief powers are quite broad. The War Powers Resolution limits his ability to engage unilaterally in military action, by requiring him to report to Congress within 48 hours, and if Congress disapproves, troops must be removed after 60 days. However, this law pertains to armed forces, and would not apply to remotely-launched missiles. Additionally, it is unknown if the resolution is unconstitutional (presidents say it is). No law at all requires POTUS to obtain permission from someone else, in order to engage in a military action.

Article 90 of the UCMJ states that it is a punishable offense to "willfully disobeys a lawful command of his superior commissioned officer". The manual also states that

An order requir­ing the performance of a military duty or act may be inferred to be lawful and it is disobeyed at the peril of the subordinate. This inference does not apply to a patently illegal order, such as one that directs the commission of a crime.

Murder of a civilian is an example. It also says

The lawful­ness of an order is a question of law to be deter­mined by the military judge.

"Shocking the conscience" is not a grounds allowing disobedience. One can only conjecture how a military judge would evaluate the lawfulness of a presidential order, when there is not a shred of legal evidence that such an order is in fact illegal: I conjecture that the order would be found to be lawful.

Answer 2

Marjorie Cohn, Professor Emerita at Thomas Jefferson School of Law, wrote an article on The Duty To Disobey A Nuclear Launch Order, and concluded:

An order to use nuclear weapons ― except possibly in an extreme circumstance of self-defense when the survival of the nation is at stake ― would be an unlawful order. Military necessity is also a well-established law of war. It allows “those measures not forbidden by international law which are indispensable for securing the complete submission of the enemy,” according to the Lieber Code. It is never necessary to use a nuclear weapon, except in certain hypothetical cases of self-defense if the survival of the US were at stake.

Finally, there is the principle of unnecessary suffering. “It is prohibited to employ weapons, projectiles and material and methods of warfare of a nature to cause superfluous injury or unnecessary suffering,” according to Article 35.2 of the Additional Protocol I to the Geneva Conventions. A nuclear attack on North Korea would kill and maim untold numbers of people.

Of note:

On Nov. 19, Air Force General John Hyten, commander of the U.S. Strategic Command, declared he would refuse to follow an illegal presidential order to launch a nuclear attack. “If you execute an unlawful order, you will go to jail,” the general explained at the Halifax International Security Forum in Nova Scotia. “You could go to jail for the rest of your life.”

Gen. Hyten is correct. For those in the military, there is a legal duty to obey a lawful order but also a legal duty to disobey an unlawful order. An order to use nuclear weapons ― except possibly in an extreme circumstance of self-defense when the survival of the nation is at stake ― would be an unlawful order. ....both the Nuremberg Principles and the Army Field Manual create a duty to disobey unlawful orders. ...The president can only use military force in self-defense or to forestall an imminent attack. There must exist “a necessity of self-defense, instant, overwhelming, leaving no choice of means, and no moment for deliberation,” under the well-established Caroline Case. A president has no lawful authority to order a first-strike nuclear attack. ...The president can only use military force in self-defense or to forestall an imminent attack. There must exist “a necessity of self-defense, instant, overwhelming, leaving no choice of means, and no moment for deliberation,” under the well-established Caroline Case. A president has no lawful authority to order a first-strike nuclear attack. Military necessity is also a well-established law of war. It allows “those measures not forbidden by international law which are indispensable for securing the complete submission of the enemy,” according to the Lieber Code. It is never necessary to use a nuclear weapon, except in certain hypothetical cases of self-defense if the survival of the US were at stake.

Finally, there is the principle of unnecessary suffering. “It is prohibited to employ weapons, projectiles and material and methods of warfare of a nature to cause superfluous injury or unnecessary suffering,” according to Article 35.2 of the Additional Protocol I to the Geneva Conventions. A nuclear attack on North Korea would kill and maim untold numbers of people.

If the president ordered a nuclear strike, Gen. Hyten said he would offer legal and strategic advice, but he would not violate the laws of war simply on the president’s say-so. Additional information surrounding this conclusion is detailed in the referenced article.

Answer 3

I highly recomend that you watch the opening scene of "War Games" which deals with this scenario and is considered to be highly authentic launch procedures from the soldier's perspective. As depicted in the film, a launch team of two individuals are locked into a room with now outside contact save for the equipment printing the orders for the duration of the shift. When the equipment print the order, the soldier's authenticate it and follow the instructions. They have no "window" to look out, no TV to check on reporting, and no reason to suspect that the order is anything but lawful. The film also depicts the response if the order is not carried out. Keep in mind that this may not be a first strike but a second strike and the officers in the command bunker have no way of knowing this (or even if any other missal was ordered to launch). There assesment is that the order is valid, it instructs them to launch and what to hit, and that's all they will know until they are debriefed (presuming they aren't killed by an incoming attack).

At the top level, the only way to countermand a launch order is if the Secretary of Defense fails to confirm that the order is authentic (that is, the President issued it). The SecDef has no veto over the order if it is in fact given by the President. He only has to say it was definitely an order from the actual sitting President (and not, say, someone using a Nuclear Football that was accidentally left behind during a Presidential event... cause they have left Nuclear Footballs behind... no compromise took place, however.). Once that issue is given, it is considered lawful and anyone further ordered to act according to that order is in a blackout state to have no information other than that the order lawfully told them to launch.