Nuclear materials, something the president has been talking about since his days in the senate. this was an early issue he cared about. also, this growing isolation of iran, interesting to hear mcdonough to say it's not about sanctions. it seems to be a new tact. did you hear that, chuck? >> it is. that's why we're saying the symbolic nature of china signing on board, because they do feel like they need to figure out a way to get european union and other nations to sign on. this is nuclear chess. you do one thing symbolically and then you hope a whole series of dominos fall that you're trying ...