New North Atlantic Treaty
New North Atlantic Treaty is an Outer Colonies faction that is composed of various liberal and social democracies, and parlamentary monarchies (that are in fact democracies with symbolic role of the kings). Common denominators are democratic elections, existence of private property (sometimes contested by various ultraleft movements, but never really denyed), state divided into judicary system, legislature and executive powers, and so on. They banded together following Unification Wars to oppose the onslaught of extremist movements, who spread through Galaxy like wildfire.
A love/hate relationship.
While NNAT states in most cases aren't really all that religious, they are still one of two possible allies for RPC (the second being Ancien Regime), and the one more likely at that. As such, they are force to cooperate against extremists, even though they aren't overly lovey dovey with eachother.