You do know that OTL, two of the Balkan states are already in the EU, and the rest are working towards joining? And all these states have piddly power compared to France, Germany, and the UK (to say nothing of Italy, or even Poland)?
As much as Europe is heading towards political federation, it will never happen because if you add all the Balkan states to the EU, you are just going to end up with the issue that Yugoslavia was in during the late 80s. The Croatians will never accept the idea of the Serbians having more power than them in the European Parliament.
And the Canadians would NEVER opt for Union with the US. The Quebec independence movement would explode again!
Long story short, you can never have a NATO composed of a unified North America and a unified Europe. The internal struggles are too great to deal with.
We'd lose our healthcare and our Cuba policy, for starters...
Likewise it depends on how much a Federal Europe spends on defence compared to the Americans (Washingtion in OTL dominates NATO spending).
the us dominates global defence spending, so that is actually a non-issue
top 3 in defence spenders:
us $640 Bn
Eu $231 Bn
China $188 Bn
a unified europe is unlikely to let itself dominate by the us just because they have a higher defence spending.
what would change is that there would be no american commander of nato europe, and lots more changes, since the whole treaty probably would have to be rewritten, as a bilateral treaty between equals.
If America is going to be spending far more on defense than the Europeans then it is invertible that they would take a bigger share of the burden and thus demand a bigger say on how NATO is run.
Also would this mean then that Washington would have to pull its forces out of Mainland Europe?
the political reality is that in a unified europe, the supreme military commander will be european, anything else is political suicide.
Nato has been created with a single thought, to protect Europe against russia and its allies. and in a 2 country nato (which will not be called that anymore under those conditions) things will be very different.
simply because letting the us decide things means Europe compromises on its sovereignty, and that is always political unacceptable.
especially since washington has the habit of treating Europe like its peon.
i expect Europe to stand its ground political, and expecting it to be a treaty between equals. after all it was the us own decision to spend so much on defence, not the decision of Europe, and most of that us defence money isn't spent on Europe defence related things.
Anyway by the looks of it you might as well scrap the whole NATO structure and turn it into a European-American alliance like ANZUS then?
How much of a "European Millitary" could a Federal Europe afford compared to the US?
i think that would be more likely
financially: more than the us
GDP EU 18,9T$ GDP US 16,7 T$ (18,5 with canada)
tax income: EU 6615B$(estimated). US 4492,3 B$ (with the average tax income EU approx 35% of GDP, US 26,9%)
political will to do so is another thing in Europe though.
What would Canada lose (and don't say becoming more neo-liberal, Canada joining will push America way from that) if they joined? .
Being Canadian, which is more important than anything else really.
If Europe spent 5% of their GDP on defence it would be around $100 billion more than what America currently spends on defence (their share of GDP is also 5%). I would agree political will is another story but if this POD is possible maybe this will push it to that direction.
there was a reason why i included the tax income, because it shows a more realistic view how easy it would be to bear.
5% of european GDP compared to 5%of US GDP isn't the same.
the european 5% would be actually equivalent to a US 3.4% with the regards of the financial impact since europe has around 150% of the tax income of the US
if one looks at the list, then you can take $800 pp as a good average, and 900 as a peak what seems possible in current situation
estimate at euro population in this scenario approx 570-580M (since it includes Ukraine etc too)
then
$800 pp is 456B (406B in current eu size)
$900 pp is 513B (456B current)
Would GDP make more sense since we are talking about the overall burden? Likewise to increase defence spending while avoiding cuts elsewhere then taxes will have to rise or there would be less tolerance of tax evasion and avoidance.
This shows the potential Europe has on the geopolitical stage if they are willing to place themselves there.
the expanded 570-580M figure is EU+EFTA+Ukraine, and most of the former Yugoslav countries (since that was what the OP specified, all of europe except Russia and Belarus)
i do not think European defence spending has to be increased that much, neither would there be an excessive tax rise, first of all there are enough places to cut money from (lets face it restructuring the agri subsidies is long overdue anyways), and doable within the current tax income.
even if you aim for a total budget of around 350B (currently around 225B) that would allow for a sizeable defence force, and the biggest cost reduction would be a unified armed forces structure (far less overhead than all separate countries, cheaper production due to higher numbers involved of equipment etc )
Any idea of what the relationship might be like between a unified North America and Europe as military allies? Will these superpowers be capable to have comfortable and friendly relations to eachother?
good question, considering that a few years ago we were on the edge of a trade war.
all would depend on the situation, if russia collapses again it is bound to drift towards europe (since about 60% of its trade is with europe).
in the long run they probably will become competitors.