It shall be discovered that the "memos" did come from a staffer, perhaps oppo researcher, on the Kerry campaign. The "memos" were only good enough to sneak past the overly credulous Dan Rather and his producer at CBS, yet not good enough to withstand even cursory examination by those with minimal knowledge of the subject but no emotional connection to the material. The source of the "memos" will be a Democratic die-hard, but not for Kerry. While this person will go down claiming all the while that they were only trying to get Bush, the truth is that the unknown staffer will have other hidden loyalties.
There is no way that the Bush campaign is responsible for this mess. The spin would have to go exactly their way. If the "memos" were left unchallenged, it would have made Bush seem even more like a diletente. If the forgeries were too quickly traced to the staffer (and you can bet that someone in the Kerry campaign is asking who the hell released these things) and then to the plot master, then the mainstream media would be on them like a great white on a hooked tuna.
My belief, it that the unknown leaker is a hard core democrat. That is, the hard core that gets the tingles with the thought, "Hillary '08".
Salt is available next to the lime and tequila for the necessary grains.