Short version: because politics are involved, it is statistically likelier that the Swedish sex charges against him are trumped up (or at least selectively applied):

…we tend to get lost in the most immediate details and we forget the underlying context.

I was reminded about this recently when reading WikiLeaks founder Julian Assange, who is wanted for questioning by Swedish authorities on charges that that he has committed sexual assault. People have spent a lot of time debating the details of the charges, which invoke a number of difficult questions about what constitutes consent during a sexual encounter. Commenters differ in their interpretations both about the facts intrinsic to the case and in their readings of Swedish law.

I certainly do not intend to resolve those debates, although they are by no means uninteresting or unimportant. What I would suggest, however, is that it would be a mistake, from the standpoint of Bayesian reasoning, to think we can separate out the merits of the charges from their political motivations.

There is virtually no chance that the case against Mr. Assange would have proceeded in quite the same manner if he were instead an itinerant painter named Jens Andersen, or a traveling salesman named John Andrews — instead of an internationally renowned provocateur. Indeed, the charges might not have been brought against Mr. Assange in the first place. Sweden has among the highest rates of reported rape cases in the European Union. But unfortunately, few cases are brought to trial (only between 10 and 20 percent, according to various reports), and fewer still result in convictions.

That alone might not tell us much. There are other ways, however, in which the behavior of the authorities has been quite unusual.

The initial warrant in the case against Mr. Assange had been issued in August. But it was  revoked the next day, due to what the lead prosecutor cited as a lack of evidence. It was only last month – just as WikiLeaks was preparing to release a set of confidential diplomatic cables – that Sweden again issued a warrant to detain him.

After turning himself in to the authorities in London, Mr. Assange was initially denied bail (although he has since been awarded it) — which is particularly unusual given that Swedish authorities have still not formally charged him with a crime, but merely want to bring him in for questioning. Most unusually still, Sweden had issued an Interpol red alert for Mr. Assange’s arrest, something they have done for only one other person this year accused of a sex crime: Jan Christer Wallenkurtz, who is suspected of multiple cases of sexual assault against children.

The handling of the case has been highly irregular from the start, in ways that would seem to make clear that the motivation for bringing the charges is political.

Does that mean, however, that the underlying charges themselves are spurious, trumped up, outright false, or otherwise dubious? (Some have speculated, for instance, that Mr. Assange may have been entrapped.) No, not for certain, of course — but it does have an impact on the probabilities.

And Nate Silver knows him some probabilities.