That's the more interesting topic, and it came up when I visited the NYC LW crew last week.

My take is that, if TDT really is superior to other decision theories, then a society of majority-TDTers should not lose out to "mindless drone decision theorists" (MDDTers) simply by all individually refusing to vote, while the MDDTers vote for stupid policies in unision.

The TDTers would, rather, recognize the correlation between their decisions, and reason that their own decision, in the relevant sense, sets the output of the other TDTers, so they have to count the benefit of voting as being more than just "my favored policies +1 vote". I conclude that a TDTer would decide to vote, reasoning something like "If I deem it optimal to vote, so do decision makers similar to me."

The others there disagreed that TDTers would vote in such an instance, claiming that other methods of influencing the outcome exceed the effectiveness of voting in all situations.