Pyongyang and Washington differ on what should come first -- disarmament or the reactor, which is more proliferation resistant than other kinds of reactors such as graphite-moderated reactors that can be used to produce fissile material.
The timing and sequencing needs to be negotiated by the six countries -- the two Koreas, China, Japan, Russia and the United States. The next round of the talks is scheduled to start next month, probably around November 7.
The North has in the past set out tough positions ahead of talks as a way of maximizing its room to negotiate.
I'm no diplomat. But might I humbly suggest that the proper sequence should be Kim Jong-Il hung from a lamp post by angry North Koreans and then the nuclear reactor gets built.
We can just explain this opening gambit as a way of maximizing our room to negotiate.