There is also a deeper problem with the slap on the wrist. It lets the Saudis believe the U.S. needs them more than they need us. It effectively puts the Saudis in control of the alliance, despite the fact that they are a much weaker power. As Robert Kagan told me in an interview this week: “Unless are you willing to punish them for this misbehavior, then they own you.”

What about the more severe response? Saudi Arabia would definitely get the message — and other U.S. allies would understand there are consequences if America recalled its top diplomat and supported a UN resolution. But that risks undermining Prince Mohammed, and the U.S. has an interest in his success with promised reforms like greater women’s equality, a more open economy and a less radical clergy. What’s more, less U.S. military engagement in Yemen will likely lead to more civilian casualties.

Which course it chooses will say a lot about the Trump administration’s values. The first priority for U.S. officials should be to join the rest of the world in demanding a full accounting of what happened in Istanbul.