Could 1960s idea have made N. Korea nuke program ‘impotent and obsolete’?

Zenith Star SDI laser concept didn't fly   (LMC image)
To my surprise and pleasure I heard today from a man who ran Project Defender for the Defense Advanced Research Projects Agency (DARPA), ’way back in the 1960s. He had been a key information source when I wrote my book on 1980s space defense concepts, The SDI Enigma. Now I reflected that, in the best of worlds, one of his projects could have been taken more seriously in the 1960s and upgraded in the 1980s in preference to laser weapon...