The Globe and Mail reports in its Wednesday edition that on Monday, the Houthis, an Iran-backed armed group in control of the northwestern quadrant of Yemen, threatened to impose a maritime blockade on Saudi Arabia. Guest columnist Thomas Juneau writes that to do this, they would threaten maritime shipping in the southern part of the Red Sea, on Yemen's west coast. This would potentially block the Bab al-Mandab, the southern entrance to the Red Sea, through which about 10 per cent of global trade normally transits daily. When the United States and Israel launched their war against Iran on Feb. 28, many analysts raised the possibility that in support of their Iranian partner, the Houthis might retaliate by resuming their attacks in the Red Sea. It is plausible that the U.S. and Israel have inflicted enough pain to make the Houthis cautious. The situation today has changed, however. Iran perceives that it is winning the war. Its leadership assesses that Washington is backed into a corner and has run out of viable options to force the reopening of the Strait of Hormuz. Tehran's objective now is to institutionalize the new reality: that Hormuz is theirs to control indefinitely. The Houthis appear to have a similar objective.