The US is 50 separate countries that have voluntarily chosen to speak as once voice in matters of Foreign Policy, Foreign Trade, Wars, the Coining of Money and such.
You need to study federalism in much greater detail.
If you look back at the way this started, you would see that they weren't 50 separate countries that just came together.
There 13 that joined in the revolution against English rule and the other 37 came in over time.
There are currently 28 individual countries, in the EU, that are trying to make something work.
We had 3 join in December of 1787
8 between January and July of 1788
1 in 1789, 1790, 1791 1792.
Another 1, 4 years later, in 1796
I in 1803, which was 7 years later
The another 9 years for one to join in 1812
The 4 more years for 1 to join in 1816, then 1817, 1818, 1819, 1820, and then 1821
Then 15 years for 1 in 1836 and another in 1837
8 years later 2 more joined, in 1845
Another in 1846
Then 1 @ in 1848, 1850, 1858, 1859, 1861, 1863, 1864, and 1867
Then, after 11 more years, 2 in 1889, followed by 2 in 1890
After 6 more years, 1 in 1896
Then 11 years later, 1 in 1907
The last 4 occurred with 2 in 1912 and 2 more in 1959.
So it took almost 172 years and started with a way and survived a civil war.
Now you have to consider that the EU countries have a much longer history of being individuals "States" and a some of them have centuries old animosity towards each other.
