In the sites that I frequent, "containment" boards or threads work well to reduce community tension about controversial topics.

Plus, in LW's case, the norm against political discussion makes it so that any political discussion that does take place is dominated by people with very strong and/or contrarian opinions, because they're the ones that care more about the politics than the norm. If we have a designated "politics zone" where you don't have to feel guilty about talking politics, it would make for a more pluralistic discussion.