Afghans head to the polls today.Christian Brose at Foreign Policy's Shadow Government blog outlines a few worst case scenarios. One worst case outcome is the Iran scenario -- a disputed election result, allegations of fraud, and a drawn-out political fight laced with street protests and sporadic violence. This could be set off by either a narrow Karzai win or a suspicious Karzai blow-out (Ahmadinejad style). One could imagine days, even weeks, of protests by the losing candidates' supporters demanding a recount, or a revote if none is declared, ultimately leading to an unpopular Karzai...