The pay raise put forward this week was not initiated by Congress to give themselves a pay raise. It was an executive order issued by President Barak Obama. In fact, they voted to reenstate the pay freeze. Maybe the President was doing what he always does to get what he wants, throw money at whomever he is trying to win over. It worked to win him re-election, maybe he thought it would work to get his tax increases pushed thru.

http://www.weeklystandard.com/blogs/obama-orders-raise-biden-members-con...

http://www.washingtonpost.com/blogs/post-politics/wp/2013/01/01/house-pa...