The third theory is the most plausible: The Democratic memo reveals that much of what the media has been focusing on for the past six months has been a set-up job. The staff and Democratic members of the Senate Intelligence Committee have been selling story after story (think the Niger yellowcake and "imminent" threat controversies). Out of whole cloth, they have contrived an ambiguous but ominous speculation about the Bush administration's sinister motives for invading Iraq. Now, through this one memo, they have been revealed as nothing short of cynical political operatives. And the reporters who ran with their hints.
In fact, that's such a good statement that everyone should simply copy and paste it to a letter to the editor of their local newspaper.