Again, I would just take Mark's previous words. I'm not an expert in this area. The Europeans have to manage their own security, in a sense. They don't fully rely on NATO for those outcomes. They're a parallel security apparatus that has evolved in parallel with the NATO apparatus.
My European colleagues have said that in some respects they feel very threatened right now, because they can't rely on what they consider to be a U.S.-guaranteed security in their future. Maybe this is an example of that, just a more effective and efficient signing of an arrangement that can produce some more guaranteed security results within those core countries.