An alternative without programming changes would be biweekly "incisive open threads", similar to Ozy's race-and-gender open threads
Feel free to start a "political thread". Worst case: the thread gets downvoted.
However, there were already such threads in the past. Maybe you should google them, look at the debate and see what happened back then -- because it is likely to happen again.
and downvoting customarily tabood in them.
Not downvoting brings also has its own problems: genuinely stupid arguments remain visible (or can even get upvotes from their faction), people can try winning the debate by flooding the opponent with many replies.
Another danger is that political debates will attract users like Eugine Nier / Azathoth123.
Okay, I do not know how to write it diplomatically, so I will be very blunt here to make it obvious what I mean: The current largest threat to the political debate on LW is a group called "neoreactionaries". They are something like "reinventing Nazis for clever contrarians"; kind of a cult around Michael Anissimov who formerly worked at MIRI. (You can recognize them by quoting Moldbug and writing slogans like "Cthulhu always swims left".) They do not give a fuck about politics being the mindkiller, but they like posting on LessWrong, because they like the company of clever people here, and they were recruited here, so they probably expect to recruit more people here. Also, LessWrong is pretty much the only debate forum on the whole internet that will not delete them immediately. If you start a political debate, you will find them all there; and they will not be there to learn anything, but to write about how "Cthulhu always swims left", and trying to recruit some LW readers. -- Eugine Nier was one of them, and he was systematically downvoting all comments, including completely innocent comments outside of any political debate, of people who dared to disagree with him once somewhere. Which means that if a new user happened to disagree with him once, they usually soon found themselves with negative karma, and left LessWrong. No one knows how many potential users we may have lost this way.
I am afraid that if you start a political thread, you will get many comments about how "Cthulhu always swims left", and anyone who reacts negatively will be accused of being a "progressive" (which in their language means: not a neoreactionary). If you will ask for further explanation, you will either receive none, or a link to some long and obscurely written article by Moldbug. If you downvote them, they will create sockpuppets and upvote their comments back; if you disagree with them in debate, expect your total karma to magically drop by 100 points overnight.
Therefore I would prefer simply not doing this. But if you have to do it, give it a try and see for yourself. But please read the older political threads first.
I don't understand this word "was" - I just lost another 9+ karma paperclips to Eugine Nier.
Not to put too fine a point on it, but this seems less like a problem with political threads and more like a problem with someone driving most of the world's population (especially the educated western population) away from existential risk prevention in general and FAI theory in particular.
(I hope that is the least click-baity title ever.)
Political topics elicit lower quality participation, holding the set of participants fixed. This is the thesis of "politics is the mind-killer".
Here's a separate effect: Political topics attract mind-killed participants. This can happen even when the initial participants are not mind-killed by the topic.
Since outreach is important, this could be a good thing. Raise the sanity water line! But the sea of people eager to enter political discussions is vast, and the epistemic problems can run deep. Of course not everyone needs to come perfectly prealigned with community norms, but any community will be limited in how robustly it can handle an influx of participants expecting a different set of norms. If you look at other forums, it seems to take very little overt contemporary political discussion before the whole place is swamped, and politics becomes endemic. As appealing as "LW, but with slightly more contemporary politics" sounds, it's probably not even an option. You have "LW, with politics in every thread", and "LW, with as little politics as we can manage".
That said, most of the problems are avoided by just not saying anything that patterns matches too easily to current political issues. From what I can tell, LW has always had tons of meta-political content, which doesn't seem to cause problems, as well as standard political points presented in unusual ways, and contrarian political opinions that are too marginal to raise concern. Frankly, if you have a "no politics" norm, people will still talk about politics, but to a limited degree. But if you don't even half-heartedly (or even hypocritically) discourage politics, then a open-entry site that accepts general topics will risk spiraling too far in a political direction.
As an aside, I'm not apolitical. Although some people advance a more sweeping dismissal of the importance or utility of political debate, this isn't required to justify restricting politics in certain contexts. The sort of the argument I've sketched (I don't want LW to be swamped by the worse sorts of people who can be attracted to political debate) is enough. There's no hypocrisy in not wanting politics on LW, but accepting political talk (and the warts it entails) elsewhere. Of the top of my head, Yvain is one LW affiliate who now largely writes about more politically charged topics on their own blog (SlateStarCodex), and there are some other progressive blogs in that direction. There are libertarians and right-leaning (reactionary? NRx-lbgt?) connections. I would love a grand unification as much as anyone, (of course, provided we all realize that I've been right all along), but please let's not tell the generals to bring their armies here for the negotiations.