As you know, North Korean dictator Kim Jong-un is the most notorious dictator. Numerous human rights abuses have carried out in NK.
Systematic, widespread and gross human rights violations have been and are being committed by Kim Jong-un. In fact, the gravity, scale and nature of these violations reveal a state that does not have any parallel in the contemporary world.
If the US State Department declare Kim Jong-un a persona non grata in America, it can be a real, immediate threat to the top leadership.
Petition to Declare Kim Jong-un as Persona Non Grata in U.S.