This is Trump we're talking about, and I wonder what is not a provocation? I'm sure he'll can manufacture one, in any case.
As for safe guards, hopefully it's better than when President Nixon was about to resign, but is the moral character of the people around him better than at that time? I doubt that.
The Madman and the Bomb:
"...
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.”
..."