The U.S. ambassador to NATO has, when one thinks about it, just one job. No matter who holds the job, the U.S. ambassador to NATO has many priorities, as one would expect for a role that involves dealing with dozens of countries and trying to get them to agree on a coherent defense policy. But one would think that not provoking a nuclear war with Russia would be at the very top of the ambassador’s list of priorities. This seems like a no-brainer, but it helps to focus on the simple things. The United States has a special obligation to be the “adult in the room” and to keep the alliance focused on constructive responses to collective threats.