Should NATO be folded in favor of a European Union unified command?

[Pannonian]

Unless the other NATO powers had specifically advised Romania that they would not support Romanian efforts outside the extent borders which, in fairness to Sarmatian's general point, might well be the NATO attitude.

A comparable case might be the US troops in Korea. Would NATO be obliged by treaty to respond if North Korea steamroller the US troops there? My guess would be that it's outside the treaty's remit, and any response would be volunteers only.