However, by 2079 all "United Earth nonsense" had been abolished, as Q reminded Data in "Encounter At Farpoint"
The statement came from Q, and is therefor suspect as far as being
completely true.
However Data never tried to refute it, nor did any other member of the away team. And Picard's line about "Kill All The Lawyers" very well backs up Q's claim about the court being from that era.
It's unlikely given the death toll of the war that the third world war was in fact world wide, nor do I think the "post atomic horror" was either. The PAH existed in some areas only, and any growth/participation in United Earth in those areas would have had to wait until those peoples got their act together.
600 hundred million dead? That's quite a large number, plus I would also suggest that the War lead to the destruction of a lot of records from before 2053, so Riker's number may've even been off by a a few billion. Not to mention but the majority of the world's major cities and governments had been wiped out by WWIII. Let's see: Ottawa Canada currently has about 1 million people, Toronto about 2.5 million, Washington D.c. Is around 12 million, Delhi India is close to 25 million (and by 2030 their population is expected to bloom to close to 36 million), Tokyo Japan is currently around 36 million, Sydney Australia is around 4.5 million, London UK is about 8 million...need I go on? So if the major cities were destroyed, you could easily see the 600 million dead. Plus as Spock noted in "Space Seed", when he was looking up information about Khan, very few records from about the 1990's through to the mid-21st century survive.
which was apparently the beginnings of what would become the United Earth government in 2150 ...
Beverly used 2150 to refer to the formation of a "world government," she never refer to United Earth in connection to that date. That the body that was formed in 2150 was in fact "United Earth" is both possible and debateably not the case.
In 2150 the mentioned world government and United Earth could have been (at the time) two entirely separate organizations.
That doesn't even make sense. As Picard noted the Hegemony was a very loose affiliation between European states. It had no real power, just like the UN of today has no real power.
We're only told that the European Hegemony was formed in the early 22nd century, but were not given an exact year of the formation. 2123 refers to the beginning of the use of the distress beacon.
2123 is "early-22nd century". And the distress beacon was a common EH distress beacon.
The Mariposa was launched in November 2123.
United Earth existed in some form
a functioning world government
It wasn't my intent to suggest that United Earth was a world government in 2067, only that it already exist in some form.
It is highly doubtful that any sort of world government or UN organization had been setup by 2067, considering that WWIII had ended in 2053, and in 2063 the US still looked like Europe had in the late-1940's.