Yo, Donald! Decapitating Heads of State is a Risky Business
It's worth recalling that one reason for the Ford executive order against killing other countries' leaders was concern, among those who had bought the official theories about the Kennedy assassination, that it might have been Castro's retaliation for all the US efforts, including under Kennedy, to kill him. That's something "warrior" Trump might want to cogitate on before he contemplates trying to 'take out' other foreign leaders.
But there are other reasons why launching an attack on North Korea to kill Kim and eliminate his nuclear and missile capability is a lousy idea. One is that such an action would almost certainly mean the contamination of part or even much of North Korea with nuclear fallout and radiation, and perhaps South Korea too. Another is that given the long history of US “precision” targeting going terribly wrong (as in Iraq and Syria lately), it would likely mean much death and destruction for the long-suffering North Korean people. It would also almost certainly mean a long period of utter chaos in a country that for nearly three-quarters of a century has been ruled by one absolute tyrant or another, in which there is simply no organized system of governance at lower levels to handle anything, from delivery of health services to distribution of food. Add in the inevitable pent-up demand by many North Koreans for vengeance against those who for so long oppressed and starved them, and killed family members, and if you think the chaos that followed the US invasion and overthrow of Saddam Hussein and the Baathist leadership of Iraq was bad, or that the chaos of the US overthrow of Gaddafy in Libya was bad, you ain’t seen nothing yet, should North Korea’s leader gets offed in a US air strike.
In theory, China, South Korea or Japan could step in with troops, money and civilian personnel to help reestablish some kind of order and peace, while preventing the rise of yet another tyrannical government, but none of that is likely. The Chinese would probably not want to take it on, the Japanese are viewed negatively as a former colonial power, and South Korea may not want the financial burden of rescuing the North, which would be staggering. Meanwhile, while the US could relatively easily, and at minimal cost, “take out” North Korea’s missiles, nukes and leadership, especially in the case of the Trump administration, there is absolutely no interest in taking on the costs of occupying and subsidizing the rebuilding North Korea following such an ill-conceived attack. The US has never been good at picking up the pieces after destroying a country, and under Trump, it is likely to be even less concerned about such after-effects of its violence.
Will such likely outcomes of an attack deter the US from ending the long-standing ban on killing national leaders and launching a blitzkrieg on North Korea aimed at “taking out” Kim?
It’s hard to say, but with Trump abandoning his domestic campaign promises left and right, turning domestic policy into a giant give-away to the rich and the Wall Street banksters, and in the process alienating most of his political base, he seems hell-bent on diverting Americans' attention abroad by taking dramatic military actions that make him appear decisive and powerful.