With two weeks before the election, most political followers are glued to national and swing-state polls. But some junkies and journalists swear by Intrade, an online betting market where investors place money on the next president (among other things).

But this morning, something very weird happened on Intrade. Mitt Romney began the day trailing the president 60 to 40 (i.e.: his chance of winning was priced at 40%). Suddenly, Romney surged to 49%, and the president's stock collapsed, despite no game-changing news in the press. The consensus on Twitter seemed to be that somebody tried to manipulate the market.