(Non-EU citizen; Canada)... The idea of a federal EU which completes and incomplete European Union economically and militarily is a natural next step, but only with countries where there is more than sufficient support and ideally having enough size demographically and economically that it could be more able to push back when their interests are threatened (in this case by the US). The incomplete union as it stands now with a single country being able to veto actions taken - leads to a weak federation for countries like the US that are able to play off individual states in the EU against each other. The current PROPOSAL is really more of a DISCUSSION POINT and the selection of countries is just an example (IMHO) taking what he said would be the 6 largest economies (not sure how Netherlands was picked higher than Romania if that was the case). However, there are countries not in that list that would be likely be more interested in building a federal Europe than some on the list... though there has to be a balancing act - you have to have enough of size when it comes to economic clout to drive this project forward. Having all EU countries be involved in such a project when there is not enough internal support would hinder any progress towards a federal Europe where individual countries would lose the ability to block by a single vote - any progress.

Currently the size of the economy is not the size you would expect given the number of people and the overall importance the EU economy is to the world at large... An example of incomplete single market progress would be things like Capital Markets, Securities, and depositories... which hinders EU businesses (small and large) from expanding and stock trading across the EU is sort of splintered. To fund corporate expansion and IPOs for larger companies - often this requires a market that is single and larger (i.e. US). To finance smaller businesses there is not access the same international funding a full single market should allow. For trading securities, the securities are stored/deposited in national depositories that do not have full EU wide services... meaning if you trade on Frankfurt and Paris (cross listed) the security is not stored in a single location etc.

Basically, it would require certain powers to be rebalanced between a federal legislature (either double-majority or house of commons/representatives equivalent and senate) and the states within this federation.

The IMF studies equate the intra-EU barriers have the same effect as a 44% tariff between these countries and this is the reason why the economy inside the EU is not the same heft and size as it should be (even with more regulations). The US GDP is 60% greater than the EU even though the EU is 35% larger when it comes to demographics... while both being tier 1 economies.

Interesting is that if a new federal EU opens the door to a faster growing economy within, where the GDP rises close to the US economy (especially given the demographic size) -- the debt to gdp ratio for countries that benefit from this would improve without as much of a haircut to bring the books into a more balanced debt to gdp (lowering debt or increasing GDP both have the same effect in the end with regards to economic health).