After all, he asked for it.
In a recent campaign appearance in Virginia, the President remarked:
Ultimately, I think, Mr. Romney is going to have to answer those questions because if he aspires to being president, one of the things you learn is you’re ultimately responsible for the conduct of your operations.
The Obama campaign has been in all out assault mode on Mitt Romney since it was discovered that Romney may not have completely severed his relationship with Bain Capital after 1999.
There are actually more then three reasons, but this is a good place to start. Feel free to add to it and remember, November will be here soon.