What "uniform/arm-patch" was Archer wearing in First Flight?
What sort of asshole calls itself United Earth to the point of excluding the ununited parts of Earth from it's collection of Nation States?
Is it possible that The "World Government" Crusher was talking about and the institution referred to as "United Earth" are completely different organizations?
United Earth could be like the UN where they all talked before and after the formation of the Wolrd Government. There would be an overlap of powers, if the United Earth was completely deballed, but it wouldn't be too difference between how the US State and US Federal Governments interact.
I remember there being a Vulcan Embassy in Canberra.