Ever since nuclear weapons were invented, people have worried about how they could be abused. Politico has an article The Madman and the Bomb about fears that Nixon would scorch the Earth on his way out.
Moreover, Defense Secretary James Schlesinger recalled years later that in the final days of the Nixon presidency he had issued an unprecedented set of orders: If the president gave any nuclear launch order, military commanders should check with either him or Secretary of State Henry Kissinger before executing them. Schlesinger feared that the president, who seemed depressed and was drinking heavily, might order Armageddon. Nixon himself had stoked official fears during a meeting with congressmen during which he reportedly said, “I can go in my office and pick up a telephone, and in 25 minutes, millions of people will be dead.” Senator Alan Cranston had phoned Schlesinger, warning about “the need for keeping a berserk president from plunging us into a holocaust.”
On Nixon’s last day in office, when he left the White House in the helicopter, the nuclear football very quietly didn’t go with him. Staff just neglected to bring it, just in case he decided he decided to launch nuclear weapons. Schlesinger had no authority to issue such orders, but did so anyway.
One thing I do credit Truman for was declaring that only the President could order a nuclear strike. Nuclear weapons weren’t a weapon of choice that commanders could use, the order had to come from the President.
During the Cold War, there was concern that in order to have a sufficiently valid nuclear threat, there wasn’t any time to waste in case we needed to respond to a nuclear attack. There certainly wasn’t time for a declaration of war, but there wasn’t even considered time to have anyone else weigh in. Not only was the President the only one who could order a nuclear attack, but a president could order one any time they felt like it. Multiple times, Trump had to be told why it was an extraordinarily bad idea to use nuclear weapons.
I think that the power of the President to order the use of nuclear weapons should be limited. We have much more advance warning that we used to have. In order to prevent a madman from launching nuclear weapons out of spite, generals should be able to countermand an order for the use of nuclear weapons. If the generals don’t think there is an imminent threat, then there probably isn’t one. This would help significantly reduce the chances of a madman scorching the Earth out of spite.