NATO expansion is a myth. It is a Russian lie. Here is the map.
After World War II the Russians militarily occupied half the European continent. The Russians picked their leaders. They wrote their laws. They brutalized their people and took whatever they wanted.
When the Soviet Union collapsed, all of these peoples who had suffered immensely under the Russians were desperate to get real security and protection from the Russians.
Russia is the ONLY cause of NATO enlargement because the people of Eastern Europe always knew they were going to be invaded again as soon as the Russians succeeded at some form of economic capitalism.
Russia is the only cause of this war.