Sorry, forgot to answer. But no, they don't. North Korea is a non-starter in most American's lives. Has always been so (the forgotten war, et al). I personally believe those who pay a little attention still believe in the clinton/albright solution, and so they think things are fixed. Plus, the IAEA makes a lot of noise.
NK is too far away to impact them...so they believe. Sorry, our countrymen are too often distracted by immediate gratification and smooth-talking politicians.
Can it (North Korea) be THAT "far away" for average Americans?? Talk about mental abandonment and insularity. Sheesh. (I kind of expected it though).