The USSR put the first objects and people into space. They also built armaments that could compete with NATO's best. Meanwhile, today in North Korea it's pretty different. Who knows what kind of systems they have in place to detect US attacks and how faulty and flawed they are likely to be and how unstable the people on top of them are and it's really something to fear.
It's easier, there the top leader decides and he loves his life: "Should you launch something at us, we know where you are (show a few slides) and will launch x nuclear weapons personally at you, wiping your entire family."
USSR had a leader but also the Politburo, in NK we have everything in one, and so far for three generations. Maybe relay the same threat to the top generals and you're done. Make it personal. Not your country, but your family will go go first. The country will follow...