Trump blockade on Iran veers from what he's done in the past

President Donald Trump has turned to naval blockades to pressure the governments of Venezuela, Cuba and now Iran to meet his demands.

But the Republican president's preferred tactic is confronting a very different reality in the Middle East than in the Caribbean.

Unlike Cuba or Venezuela, Iran choked off a crucial trade route for energy shipments, meaning the longer the standoff persists the more the global economy will suffer.

While blockades can be a successful way to bend the will of nations without risking the lives of military personnel, their economic impact can sometimes prove hard to predict if nations subject to blockades refuse to yield.