This could be the one that brings him down. We'll see the extent of it in the coming months and years. But either way you look at it, this is either criminal or grossly incompetent on his part. You got stuff like this and the IRS scandal erupting underneath you, and you say you didn't know anything - that doesn't make you look like someone who has control.
If Obama wasn't a lame duck by now (I think he was), this pretty well seals it up.