[tormeh]

First, the EU is not a defense alliance. Second, Ukraine is not in it. European countries are largely semi-pacifist. Whether that's a good thing or not is not a settled question. Going to war is generally bad for reelection in Europe whereas it is good for reelection in the US.

I do broadly agree with you that nuclear weapons have produced peace, but the EU has done quite a bit of useful work related to internal struggles, like Ireland.