The term Exiled Nations loosely describes all the nations that are not part of the UEF, either because they didnt meet the set criteria to join or because they refused to join.
This term was first used after the UN vote of the United Earth Federation Institution Act on August 13th 2035. The nations that voted against the Act were the first self branded 'Exiles' while the nations that where later denied entry were gradually regarded as such. There is a distinct difference between the two groups as most countries that were denied entry are actively trying to meet the requirements in order to eventually join the UEF.
The countries that actively oppose the UEF are the real places of political instability as a change in their government could shift their stance towards the UEF. Rumours of UEF backed covert operations to distabilise these governments are widely taken for granted by many across the globe.