IT IS not unheard of for secretaries of state to chafe over their relations with their boss. Colin Powell never had the ear of George W. Bush, and often felt bruised and frustrated as a consequence. John Kerry, to his dismay, was often left out of the loop by Barack Obama’s micromanaging White House. But there is nothing normal about the way Donald Trump has publicly scorned his secretary of state, Rex Tillerson, for holding out the possibility of talks with North Korea over its missile and nuclear programmes. Writing on Twitter, Mr Trump declared that he had told Mr Tillerson that he was “wasting his time trying to negotiate with Little Rocket Man [North Korea’s leader, Kim Jong Un]…Save your energy Rex, we’ll do what has to be done.”

What prompted this outburst was a conversation between Mr Tillerson and reporters who were travelling with him to Beijing for meetings with the Chinese leadership. Mr Tillerson had said he was “probing” the possibility of starting up talks with North Korea about its programmes. “We have a couple, three channels open to Pyongyang,” he added. “We can talk to them, we do talk to them.”

There was nothing surprising about this. While America lacks formal diplomatic relations with North Korea, messages are conveyed through the Swedish embassy in Pyongyang, which provides a consular service for US citizens. Another channel is the North Korean mission to the UN in New York. There are also so-called Track II meetings (involving academic experts and former officials), which can be used to gauge whether there is any basis for more formal diplomatic approaches.

Nor was Mr Tillerson saying anything new when suggesting that he would be interested in starting a dialogue with Pyongyang: he made similar remarks a few weeks ago. Ignoring the president’s tweets, James Mattis, the defence secretary, reiterated his support for Mr Tillerson’s “efforts to find a diplomatic solution” in a statement to the Senate Armed Services Committee on October 3rd.

Given that North Korea itself shows no inclination to begin denuclearisation talks with America and will probably consider a testing freeze only once it has a demonstrable capability to threaten mainland America with thermonuclear attack, it might seem reasonable to concede that Mr Trump had a point. Some, perhaps including Mr Trump, may even believe that the president was skilfully pursuing Richard Nixon’s “madman theory”: the idea that if you convince your adversaries that you are sufficiently unhinged to do almost anything, including starting a nuclear war, they are more likely to bend to your will.

Unfortunately, history suggests that Mr Nixon’s application of the theory in relation to Vietnam exposed the world to the risk of a nuclear catastrophe without achieving much in return. As far as North Korea is concerned, Mr Trump is sending a message to Mr Kim, to the Chinese, whose help Mr Tillerson is trying to enlist, and to America’s regional allies that investing any hope in attempting to de-escalate the crisis is pointless. If Mr Kim believes that he will be attacked come what may, effective deterrence is undermined, while nothing Mr Tillerson says or does need be taken seriously by anybody, friend or foe.

Crawling back to you

Mr Tillerson deserves only slight sympathy. He has shown little interest in representing American ideals, such as the promotion of human rights, while carrying out a botched reorganisation of the State Department that has left it hollowed out and dysfunctional. Many important posts remain unfilled—including those of assistant secretary of state for East Asia and ambassador to Seoul. He would not be much missed if he decided to quit. But on October 4th, Mr Tillerson declared that he would soldier on in his thankless job. That may not be a bad thing. Such is the damage being done to the effectiveness of American diplomacy at Mr Trump’s hands, it is doubtful whether anyone of stature would be willing to take his place.