For Europe and NATO, a Russian invasion is no longer unthinkable. Concern is growing among European nations that Putin could invade a nation in the next decade.
That could happen in as little as five years after the conclusion of the war in Ukraine. NATO maintains it is prepared to defend the borders of its 31 member states, which have collectively increased national defense spending by an estimated $190 billion since 2014, when Russia first invaded Ukraine. But that was the beginning of rebuilding what had become a hollow military network in the decades after the Cold War.