EU as a whole has actually been weak in terms of military capability and perhaps also civil defence. The end of the Cold War and the long peace had allowed a lot of us to believe that there wouldn't be a foreseeable risk of military conflict or a need to seriously prepare against aggression. Many European countries cut back significantly on their military spending and capability. And that seemed like a reasonable and popular thing to do given the circumstances. (Countries in Eastern Europe were perhaps the exception and didn't cut back, at least not so much.)

The problem is that defensive capability cannot be just built all of a sudden if it turns out to be needed after all.

Of course the reason that has become a problem is Putin's aggression and authoritarian rule.

But Europe has indeed been weak in the sense of not having maintained defensive capability. Perhaps that is, both fortunately and unfortunately, changing. (Fortunately for obvious reasons, unfortunately because it means significant spending on something that should not be necessary even though it is.)

Hopefully EU societies will remain strong and resilient in the sense they've been strong all along: strong civil society and democracy.