I thought one of the main sticking points in negotiations with North Korea was that the United States (Bush and Clinton administrations) refused to provide any military assurances. Now we've promised not to attack. Sounds like a major shift to me, but I have a lot of reading to do on the topic.
Of course, no progress would be possible if John Bolton hadn't been removed from the negotiations. Maybe he can Kim Jong-il a fallow-minded, onanistic butthead and queer the deal retroactively.