> It should be noted that sanctions have done nothing to change the behavior of North Korea's leadership to be more palatable to the West.

Sanctions aren't chosen because they are effective at changing behavior, but because they limit capacity if they fail to change behavior. The sanctions on Russia are not “we believe Putin will behave in response to the sanctions” but “we intend to destroy Russia’s economy and thereby limit it's ability to engage in aggression until and unless we are convinced that Putin has made a durable course correction.”