The attack on an Iranian oil tanker last week reignited tensions between Tehran and Riyadh. Iran and Saudi Arabia had seemingly pulled back from the brink of war last month, and tensions were on the wane as the U.S. and Saudi Arabia showed no appetite for military conflict following last month’s attack on Abqaiq. But on October 11, an Iranian oil tanker was apparently hit by explosions, and Iranian officials denounced the attack while also saying that they were still looking at the evidence. For its part, Saudi Arabia denied any involvement.…