That is surely one of the points that the NATO Secretary General called attention to. Clearly you could have something like what happened in Crimea happening in Transnistria. There are also other places, such as the city of Kherson, which is right north of Crimea. It's the transit point for a lot of the energy that goes into Crimea. That could become a point of attack by Russia.
In all of these cases, I believe the west, the United States and its allies, will have to implement a stronger policy of deterrence, a policy of deterrence that will have to, in my view, not have boots on the ground; we're not going to do that. It means helping build up local forces and helping to develop within NATO the capacity to deter Russian aggression.
We have to remember that in 1994 the United States, the United Kingdom, and Russia signed the Budapest agreement with Ukraine, when it denuclearized and gave up its nuclear weapons, that its security would be guaranteed. If that is not done, it sends a message to other countries that have nuclear weapons today. They will not give up their nuclear weapons because in the end their security will not be protected.
So the issue is really also nuclear non-proliferation, that we have to stand by Ukraine and show that a country that gives up its nuclear weapons does not have to fear that it will be invaded by its neighbours.