Candidates should be good at handling nuclear proliferation and threatening states such as North Korea [my emphasis], Iran and Pakistan. These states do not have the nuclear capacity to pose any existential risk, so they get less attention here than the primary powers, but they complicate calculations of international deterrence and might indirectly increase the risk of a major nuclear war.
What do you mean by ‘being good at threatening’? It seems counterproductive to threaten North Korea, as this could cause international conflict, and backfire by triggering action from North Korea against South Korea and possibly Japan. As argued in this article, it seems that the only options are to persuade China to increase economic pressure, or to accept a nuclear North Korea. North Korea has always been consistent and, given their goal, rational: they aim for nuclear weapons for deterrence and know that using nukes will mean assured destruction.
About Nuclear Nonproliferation you write:
What do you mean by ‘being good at threatening’? It seems counterproductive to threaten North Korea, as this could cause international conflict, and backfire by triggering action from North Korea against South Korea and possibly Japan. As argued in this article, it seems that the only options are to persuade China to increase economic pressure, or to accept a nuclear North Korea. North Korea has always been consistent and, given their goal, rational: they aim for nuclear weapons for deterrence and know that using nukes will mean assured destruction.
being good at handling {[nuclear proliferation],[threatening states such as North Korea]}
^ This, will clear up the language for the next version.