Mitt Romney has been attacked recently by the Obama campaign for not releasing his 2011 tax returns. He appeared on Fox's Fox and Friends show this morning as part of his counter-attack. You can see the full interview here but this is the part that I found relevant.
Instead of asking why Romney hasn't released his tax returns, Romney said the question should be why hasn't the Obama Administration released the documents relating to Operation Fast and Furious. As one Tweet said elsewhere, Romney's tax returns never killed anyone.