On Tuesday, Iranian president Hassan Rouhani issued an implied threat to shut down tanker shipping in the Strait of Hormuz if the United States moves to block the export of Iranian oil. The U.S. Treasury Department has imposed steep sanctions on Iran's petroleum, maritime and ports industries, among other sectors of the Iranian economy, in an attempt to force Tehran to renegotiate a nuclear accord. "America should know that we are selling our oil and will continue to sell our...