I think such forum would definately becaue U.S centric. Like you said, 50% of people is from States. Other 50% are scattered around the world. It would be forum about politics of States and maybe some bigger European countries.
I personally find politics a topic to avoid. It's both boring and lowers my level of consciousness. Politicians lie and smart people can see through their lies. Most of the posts would just criticize I think.
Still, it can't do much harm unless you care about server space.