Iran Blockade

My friend and neighbor Dave Milovich wants more specifics about what it means to get tough on Iran. He suggests a naval blockade as something between sanctions and military force. However, such a move could only come with the cooperation of the international community, as blockades deny not only the blockaded country's right to trade, but the rights of the rest of the world to trade with them. What does the U.S. do when other world powers decide to ignore us? And, of course, once you have enough of an international coalition, you might as well just use sanctions and save your ships.