NATO is seen as a deterrent to Russian expansion into the old Soviet territories as some of the states that are now democracies have joined NATO.
In the absence of a European defence infrastructure like NATO that's pretty much all they have.
Russian belligerence being invading the Baltic states. Crimea and eastern Ukraine were less clear cut than supposed for historical reasons but many in the East live in fear of the same happening to them.
But how is NATO not a military force? It’s kind of equivalent to the US military (except it includes them)... EU is similar to United States. Both are unions of independent states
In the absence of a European defence infrastructure like NATO that's pretty much all they have.
Russian belligerence being invading the Baltic states. Crimea and eastern Ukraine were less clear cut than supposed for historical reasons but many in the East live in fear of the same happening to them.