Faction Power Base Question

[Torrentara]

In the game's faction overview report, there is a section on the power base that correlates to the section in the manual on page 270. I understand how those numbers under the REL column are derived, but what are they doing? I'm trying to tie those numbers out to faction happiness, and I read the rest of the section in the manual, but it's a bit ambiguous. I'm also assuming that REL stands for relations.

[blackoutzone17]

Just a thought: besides relationship or faction happiness, power base may be the stat to calculate faction seat in elections. For example, if one faction becomes very powerful in the army, and army are getting much bigger, then in the next election this faction will get more votes.

Anyone could confirm this?