As admitted by the U.S. government, recently declassified documents show that in the 1960′s, the American Joint Chiefs of Staff signed off on a plan to blow up American airplanes (using an elaborate plan involving the switching of airplanes), and also to commit terrorist acts on American soil, and then to blame it on the Cubans in order to justify an invasion of Cuba. (more; see also)

One in seven people are convinced that the U.S. government was involved in a conspiracy to stage the September 11 attacks which killed nearly 3,000 people. A survey, which interviewed 1,000 people in the UK and the same number in the U.S., found that 14 per cent of Britons 15 per cent of Americans think the past administration was involved in the tragedy. (more from ’11)

More from ’08:

Such conspiracies aren’t always, or even usually, uncovered eventually, but such uncovering does happen often enough to make it seem socially useful to have betting markets on such questions.

Yes, such markets would have to be long term, and might need to be subsidized. And they might need to be housed in a reasonable distant and independent nation, like New Zealand.

But such market odds might offer an independent and reasonably reliable source to which doubters could turn when they weren’t sure how much weight to put on conspiracy theories vs. their skeptics. If you doubted who was behind the 9-11 attacks, wouldn’t it be great if you could turn to a betting market to better calibrate your doubts?