At
The Atlantic, David Graham writes about data from Northwestern University's Lazer Lab:
The most telling stat -- both in terms of how negative super PACs are and how much Democrats are being outspent -- is that Republican super PACs spent more trying to sink Mitt Romney during the Republican primaries than the president's Democratic allies have spent in favor of him during the entire campaign, $4.7 million to $3.2 million. Here's a screenshot of the state of the race on September 13 (click for larger size):
