This is a great idea. We should create rationalist blogs for other political factions too, such as progressivism, feminism, anarchism, green politics and others. Such efforts could bring our programme of "raising the sanity waterline" to the public policy sphere -- and this might even lay some of the groundwork for eventually relaxing the "no politics at LW" rule.
I would like to see one site to describe them all. To describe all those parts which can be defended rationally, with clear explanations and evidence.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.