Spanien drängt die EU, angesichts des Grönlandstreits eine gemeinsame Armee aufzustellen

This is a serious security question, not an anti NATO post.

A common response is that Europe already has collective defense through NATO, so a unified European army or constitutional defense clause is unnecessary. I understand that argument. However, NATO ultimately depends on political will outside Europe, particularly the United States, and that will is not immutable.

Given recent years, it no longer seems unreasonable to ask whether reliance on external guarantees introduces a structural vulnerability. Deterrence depends not only on capability, but on certainty. If an adversary believes responses may be delayed, debated, or conditioned on domestic politics elsewhere, that uncertainty itself becomes exploitable.

Another frequent reply is that Europe is too diverse politically, culturally, and historically to centralize defense. Yet fragmentation is precisely what makes divide and conquer strategies effective, especially against border states. From a purely strategic standpoint, does decentralization actually enhance security, or does it slow decision making at the worst possible moment?

I am not arguing for abolishing national armies or NATO. The question is narrower: would a binding European level defense authority and unified command strengthen deterrence, reduce ambiguity, and make Europe harder to test, regardless of who occupies the White House or the Kremlin?