This compounds because NATO needs to act collectively to effectively act militarily (maybe Poland could go it alone).
Do they? Why? They're already in a stalemate of a conflict, why would they want more fully-mobilized enemies?
35% pensions (usually also has some health care here)
35% social security and health care
15% education
15% everything else, roads, bridges, government buildings, ... (army is in here @ maybe 5%)
They're also drowning in debt, of the non-tiny, only Germany does better than the US. So they can't realistically borrow to finance this for 5 years. They're trying to cheat, and treat the EU like a separate country (meaning get investors to treat the EU as a separate state that is not on the hook for the debt of member countries but levies it's own taxes, then borrow against that, but EU countries are cheating, for example using money the EU borrowed for military purposes to fund general expenses like fixing roads)
If the EU countries mobilize the army will go to 20-25% of government expenditures easily.
That means either pensions or social security HAVE TO go down 15% (or 7.5% each). That will cause a revolt since a great many people can't survive like that. At that point there will be no choice for a lot of people but to tear the government down.
That may be the plan of course.