Many people trusted that Secretary of Defense Mattis would be able to rein in the dangerous impulses of his erratic boss who, as commander-in-chief, has the authority to order the use of military forces—including nuclear weapons.

Indeed, General Mattis may have privately assured some members of Congress that he would get into the loop to restrain President Trump if it looked like a nuclear crisis was brewing. So people are naturally worried that Mattis’ resignation will put Trump back in full control of US nuclear weapons.

But regardless of what Mattis may or may not have told members of Congress, the secretary of defense is not in the decision chain for a nuclear launch and has no ability to stop a launch order from going through. Perhaps Mattis could have talked Trump out of ordering an attack in the first place, assuming he knew the president was considering such an attack, but he had neither the legal authority nor the ability to prevent one from being carried out. Read more >