The Globe and Mail reports in its Tuesday edition that amid a barrage of violent talk, the Strait of Hormuz has now fallen under a complete blockade, with Iran and the United States facing off against each other in mirror-image military threats. The Globe's Doug Saunders writes that after dawn broke Monday, a handful of vessels slipped through the narrow passage between Oman and Iran: a Chinese freighter, a Vietnamese ship and two Iran-linked oil tankers. Then, as U.S. President Donald Trump issued threats on social media, the strait went dead. For the first time since the U.S.-Israeli war on Iran began on Feb. 28, neither Iran-linked ships nor vessels originating from Gulf Arab countries were approaching the strait from the Persian Gulf. Occurring in the wake of failed peace negotiations between the U.S. and Iran in Islamabad over the weekend, the standoff effectively pits Mr. Trump against Iran's regime in an economic endurance test. If it continues, it will have even more devastating effects on worldwide prices and supplies of oil, gas and fertilizer. That does not seem to have been Mr. Trump's intention -- he appears to believe he can reopen the strait by adding another barrier to Iran's weeks-long blockade.