On the one hand, that does make a lot of sense. Some European politicians want a more unified foreign policy, and a unified military force would give more weigh

On the one hand, that does make a lot of sense. Some European politicians want a more unified foreign policy, and a unified military force would give more weight to this desire. On the other hand, it could get very awkward if we had another situation like we had in 2002/2003 when the US were asking other countries for support in their war on Iraq. Europe was deeply divided - at least at the leadership level - in this matter. With a unified EU military, countries would have to give up a large amount of sovereignty. And there is already a fair amount of hostility towards the EU for taking sovereignty away from member states, remember Brexit. Personally, I think it would be a good idea if all countries could agree to give up their own national military. But I don't think it will happen. At most, I could see countries agreeing to move more authority to the NATO. Last but not least, there are more than 25 languages being spoken in the EU. We'd have to agree on one language being the lingua franca in a unified military if we want it to work.