Iran and NK can do whatever they want at this point. Any politician, republican or democrat, isn't willing to commit political suicide by trying to be proactive again.
The conservatives tried the experiment with Iraq, the experiment failed, and now people will second-guess and monday morning quarterback the decision for the next decade.
We need to sit back until a nuke goes off in a US harbor. Then we'll act all shocked and surprised and whichever party is in power will pledge to be "more proactive going forward". I should print-up T-shirts in advance.