Here's a little window into the method behind the madness:
http://foreignpolicy.com/2014/03/25/mad ... ite-house/
Nixon wanted to impress upon the Soviets that the president of the United States was, in a word, mad: unstable, erratic in his decision-making, and capable of anything. The American commander-in-chief wanted the Kremlin to know that he was willing to escalate even localized conventional military conflicts to the nuclear level. Kissinger understood: "I’ll tell [the Soviets] tomorrow night," he vowed. The national security advisor even rehearsed for the president specific lines from the good cop/bad cop routine he intended to put on. "The more we do now," he would tell his Soviet interlocutor, "the better." He was akin to saying: On the shoulders of reasonable men, like you and me, rests the responsibility of preventing a madman, like Nixon, from taking things too far.
It wasn’t the first time the national security advisor had been exposed to the strategic potential of madness. The concept had originated, amid the nuclear anxieties of the 1950s, in the academic circles Kissinger had formerly inhabited. It was a product of game theory, a mathematic discipline — often applied to national security policymaking — that can be used to assess competitive situations and predict actors’ choices, based on prior actions by their competitors. Kissinger himself had endorsed the concept in his writings, as a professor of international relations at Harvard, a full decade before he came to the White House. "The more reckless we appear [the better]," he told Nixon that afternoon, "because after all, Mr. President, what we’re trying to convince them of is that we are ready to go all the way."
Basically, Trump can say all these crazy things, and then his "reasonable" cabinet members can go to people in business and foreign governments, and say, "look, the future of the world depends upon us dealing with this before our madman president decides to do something crazy, so we probably should negotiate something everybody can accept right now.."