Just move 50 surface-to-surface missile (SSM) with neutron warheads up to the DMZ line south of North Korea -- Make my day or STFU already.
Call fat-boy's bluff ... negotiations and sanctions have not worked
Maybe, Kim Jong-un will have a fit and drop dead of a heart attack or stroke if the North Korean people are lucky.
North Korea will be eliminated while its missiles are targeted over the Pacific. Patriot batteries could nail North Korean missiles over North Korea. The air over the Korean Peninsula would be toxic for some time however -- maybe that would give them something to think about.