Quote Originally Posted by BigFatPie View Post
But if the UK was involved wouldnt it require a whole new set of treaties/agreements outside of the EU framework? So possibly no need for either a veto or Hungarian cooperation at all?
If UK were involved it wouldn't be an EU army, but if Hungary and Slovakia weren't involved it wouldn't be an EU army either. It would be the main military powers coming together when they agree, which is what you have now.

How are you defining EU army here? Who would decide whether it goes to war? We already have Article 5 in case of an attack, so for less than that (let's say peacekeeping in a volatile area like Ukraine) who has the final decision to send the EU army in?

Who decides which country's troops go where and do which jobs? Do individual parliaments get to ratify the decisions? It's obviously going to be unpopular for any government to go to a war zone via a Brussels decision if the ruling party doesn't agree to it. Imagine Brexit level anger x1000. It could be seen as massive Brussels overreach and kill the European project off for good.

I don't think it's possible and I don't see the benefit in trying.