More from Paul Krugman:
What I do know is that anyone who believes in Ryan’s carefully cultivated image as a brave, honest policy wonk has been snookered. Mark Thoma reviews selected pieces I’ve written about Ryan; he is, in fact, a big fraud, who doesn’t care at all about fiscal responsibility, and whose policy proposals are sloppy as well as dishonest. Of course, this means that he’ll fit in to the Romney campaign just fine.
As I said, I have no idea how this will play politically. But it does look like a move from weakness, rather than strength; Romney obviously felt he needed a VP who will get people to stop talking about him.