Joe Klein posits that the "Iranians have begun to 'negotiate' the North Korean way, through silly threats": 

These "signals" represent a complete misreading of what it takes to begin a negotiation with the Obama Administration. There’s a reason for that: the Iranians–not just the regime, but even the reform movement–have been isolated from the rest of the world for too long. They have no idea how to play the hand they’ve been dealt because they don’t know very much about the other players at the table.