How could the LWers learn to discuss it rationally if you keep it out right from the outset? Isn't talking about something rationally a skill that you acquire? Sure, most people have no idea how to discuss politics rationally (and furthermore have no idea that they have no idea how to talk about it in a rational way), but that doesn't mean that they can't learn. If you keep your kid on a leash all day because you don't trust him to make the right decisions, what exactly would be bound to happen once you get distracted and drop the leash for a few minutes?
It's inappropriate to treat politics as a separate magisterium. There's nothing exceptional about the tools we apply to the topic: we've discussed collective action problems, social signaling, and defense against rhetoric and marketing at length here, all mostly without making recourse to their political applications.
LWers can learn to discuss politics rationally by building skill in the techniques appropriate to political discussion. Using political examples directly could be expected to do this efficiently iff we successfully manage to keep the discuss...
There is a tendency to downvote articles and commentaries with a political subtext with a remark on how politics is the mind-killer. I completely understand that nobody wants his mind to be killed, however, I disagree on the employed methods. I don't think anybody can really afford to ignore politics. It's a fact about any group of even a handful of people. Thus instead of shunning politics I think it's better to build one's rational defenses. Understanding that politics is a problem is only the first step. If you stop there, there will always be a big part of life where you are not rational. Therefore I suggest that, as long as it doesn't get out of hands, there should always be room for political discussions if not on the main site at least in the discussion section.