This is great, and it's a big chunk of population, but I keep feeling like we could do better. For example, these three States could do a great job, but there's nothing stopping a bunch of the other States from bungling it (like, say, ignoring health experts and exempting certain groups from mass gathering restrictions). Then those States end up exporting infectious individuals into the States which are doing things…
If that centralized and coordinated leadership is incompetent and/or corrupt, there is no Plan B.