I think it'll be well before October. When nearly every MSM outlet hit the panic button over Mitt Romney's little birth certificate joke -- even though Obama HIMSELF has joked about the BC numerous times -- I got the feeling that they're positively paranoid that the man they championed for the highest office in the land is a crook.
Naturally, what worries them most is not the damage such a man could do to the country, but the damage such a revelation would do to what's left of their own reputations.
There is much speculation that some Obama revelation will be publicized at the RNC. The administration seems to know something big is in the works, as they have begun shuttling their rent-a-mobs to the convention area.