[TFYS]

> Europe faced a worse Russian threat during the Cold War without giving up national sovereignty.

That's because Europe could rely on the power of the US back then. If the US was just a patchwork of small independent states, Europe would very likely be a part of USSR now.

> Cooperation and military alliances do not require national suicide.

It may if your opponent is a single large country. Cooperation between many nations each looking out for their own best interests is a lot lot harder and slower than a single command structure. An alliance like that can't win against a more united enemy. The enemy can simply focus on manipulating the small weak countries individually to hamstring the alliance, as has been happening.

I would not want to be a small country caught between larger powers fighting each other, that's never a good position to be in. You'll just be a pawn on the board, getting pushed into proxy wars and civil wars by the bigger powers playing the game. I'd rather give up sovereignty willingly to be a part of a large power and a player in the game, and not on the board being played.