I can't help but think that the Obama camp has been preparing the ground for this for three months. Apparently, the Obama campaign did focus groups on the Ryan "Budget" and they refused to believe that such a thing would be proposed by any national politician.
Now the author of that plan is Romney's running mate. Having made Ryan's plan to eviscerate the federal government and return us to the Gilded Age once and for all his battle standard, Romney has now lashed himself to the mast of the HMS Rand.
All the attacks on Bain, all the attacks on taxes were designed to make the electorate believe that Mitt Romney REALLY was embracing the toxic Ryan plan.
Now Romney went and reinforced their entire tactical plan.
UPDATES: TPM has the best take on Ryan here. Another good take from mistermix. Rachel Maddow calls it the Thurston Howell/Eddie Munster ticket. A tweet: Dem operative: "We've spent 18 months trying to make House races about their plan for Medicare and Mitt Romney just did it for us overnight"