Completely seriously.

Politics is the mindkiller. But if rational people refuse to participate in politics, then all policy will be decided by irrational people, which is not good.

As the linked articles says, Bayesians should not lose against Barbarians. Rationalists should win; not invent clever rationalizations for losing. We should one-box in Newcomb's Problem, instead of complaining that the choice is unfair against our preconceptions of rationality.

I don't want to ever hear this: "Eliezer told me that politics is the mindkiller, so I refused to participate in politics, and now my children learn mandatory religion and creationism at school, cryonics and polyamory are illegal, the AI research is focused on creating a supermachine that believes in god and democracy... and it all sucks, but my duty as a rationalist was to avoid politics, and I followed my duty."

So what is the solution?

Learn to influence the politics while protecting yourself from most of the mindkilling. If that turns out to be impossible or very ineffective, then select a group of people who will use their rationality to become skilled politicians and shape the society towards greater utility, even if they lose their rationality in the process... and be prepared to deal with this loss. Be prepared for a moment when you have to say to the given person "we don't consider you rational anymore" or even "supporting you now would make the world worse". The idea is that the person should make the world better (compared with someone else getting the office) before this happens. We should evaluate carefully how much likely it is for the specific person; perhaps make some preparations to increase the likelihood.