To prevent Politics from becoming a discussion board, what if we just limited it to questions about past political events?
Wouldn't that just be History?
I think that political history is part of politics. Not to be cliche, but the past informs the present. For instance, the health care reform bill that congress passed last December wasn't generated in a vacuum -- it came as a response to previous attempts at health care reform in conjunction with the health care policy that already existed.
If it is only because of preventing to become a discussion board, then I have to say that those who have such mentality to make it here a discussion board, will do it, even if it is about history or political history. What makes a different and prevent us from an ordinary discussion board is the quality of answers and questions, the way we argue and present our views.
For preventing a site becoming a discussion board we have a lot of instruments, such as downvoting, flagging, and in worst cases baning. This is the international site, so there will be a lot of discussers with other, external, fresh point of view, and if we enforce only meritorical discussions, we have a great chance of avoiding flame wars.
There should be questions like 'What is the implication of social policy X'. Questions like 'What for we need social policy?' or 'Should we care for poor?' should be closed or redirected do Philosophy.SE.