What role did other countries play in Iran nuclear talks?

Aired: 4/4/2015 | 0:04:36 | Clip
The recently concluded nuclear talks with Iran were much more than a negotiation with just the United States. Plenty of other countries in Western Europe and Asia also played a part, but to what extent? Gary Sick, a former National Security Council official and now a senior research scholar and adjunct professor at Columbia University, joins Hari Sreenivasan to discuss.