'Not a question of whether it can be done, but to what impact' - ex-US envoy on US blockade threat

It's not the first time the US Navy has enforced a blockade - most recently, it did so towards Cuba and Venezuela, says former US special envoy David Satterfield. "It's not a question of how it is done, or whether it can be done, but to what impact," Satterfield tells BBC Radio 4's Today programme. "The Gulf is a critical global supply point, far beyond hydrocarbons - and the impact if this goes on for several more weeks is going to become quite profound, beyond just the cost of p