We have tried to discuss topics like race and gender many times, and always failed. At some point I had this idea that maybe we could get better results if we sometimes enforced political conformity within comment threads :-) For example, if we had a thread of like-minded people discussing "how to make our country more vibrant and diverse" and a separate thread about "how to stop the corrupting influence of Negroes on the youth", I suspect that both threads would have a better signal-to-noise ratio and contain more interesting insights than a unified "let's all argue about racism" thread.

Of course this requires that people from thread A resist the temptation to drop in on thread B for target practice and vice versa. Some especially fervent people may feel threatened by the mere existence of thread A or thread B. (I have actually heard from some LWers that they'd consider it immoral to create such threads.)