What website allows one to create a moderated community for discussion?

I am thinking about creating a discussion area to discuss US politics where I would be the moderator. The main things the rules would forbid are bad language and personal attacks. I would probably ban users who break the rules.

I want moderation because I want to see more fruitful discussions and some of the current political sites attract people who find it very hard to discuss things calmly.

I am interested in knowing if this option (the ability to create a discussion area) is available on an existing site, either for free or for a small cost. The only site I have found so far is reddit.com where individuals can create their own communities (known as subreddits).