The widespread fraud behind Karzai's election in Afghanistan makes it apparent that the appropriate response for a rigged election -- there and elsewhere -- ought to be more than just having those votes not counted.
When someone doesn't pay his taxes, his punishment isn't merely having to then pay them. There is always an extra penalty assessed. Otherwise there is no disincentive for tax evasion.
It ought to be the same way with any sort of chicanery around election time. If you somehow arrange for 5000 fraudulent votes, not only should those be disallowed, but you ought to have 10,000 legitimate votes subtracted from your total as well. Or something like that.
Of course, this could result in a situation whereby a politician's enemies try to arrange obviously fraudulent votes on his behalf. But politics has always been a blood sport.
The best thing the U.S. could do for Afghanistan is arrange for a legitimate election overseen by the U.S. military.
And then have the U.S. military leave.
That would also be the best thing for us.