From the outbreak of the Israel-Hamas war nearly 100 days ago, U.S. President Joe Biden and his aides have struggled to keep the war contained, fearful that a regional escalation could quickly draw in U.S. forces.

Now, with the U.S.-led strikes on nearly 30 sites in Yemen on Thursday, there is no longer a question of whether there will be a regional conflict. It has already begun. The biggest questions now are the conflict’s intensity and whether it can be contained.

This is exactly the outcome no one wanted, presumably including Iran.