Once again, the Persian Gulf is threatening to become a tinderbox and Bahrain is emerging as ground zero. Saudi Arabia, the Gulf’s preeminent power, is playing the role of antagonist in chief. Riyadh is unnecessarily provoking a stand-off with its long-time nemesis in Tehran and is leading the region into another potential crisis. The tragedy of the current course is that it is entirely avoidable. But the autocrats in the Gulf have made clear that they are willing to use any means necessary to cling to power.