Republican backers American Crossroads bought almost $8 million worth of TV time at the end of last week for ads opposing the re-election of President Barack Obama, according to Sunlight Foundation tracking of Federal Election Commission filings.
That was followed Monday by more than half a million worth of Web advertising in the same cause.
But the door swings both ways. The top Democrat-backing Super PAC in terms of independent expenditures, Priorities USA Action, spent a little over a million dollars last week on a TV buy opposing Mitt Romney.
According to Sunlight, Super PACs have spent a total of $155.5 million on all independent expenditures in the current election cycle, much of that on media buys and production with some going to postage and phone calls and other expenses. The biggest spender has been the Romney-backing Restore Our Future at 53.8 million, though most of its expenditures have been on opposing Romney's Republican nomination opponents earlier in the campaign.