Outside political groups are pouring millions into Massachusetts' U.S. Senate race.  The groups appear to be honoring a deal signed by Republican Sen. Brown and Democrat Warren designed to keep outside ads off television, radio and the Internet.  Instead the groups are focusing on mass mailings, door-to-door canvassing and automated phone calls, also known as 'robocalls' as they try to appeal directly to voters.  To date, the groups have spent more than $2.1 million on the race.

An Associated Press review of Federal Election Commission reports show those groups supporting Warren and opposing Brown have spent more than $1.3 million.  That's almost twice as much as the nearly $800,000 spent by groups supporting Brown and opposing Warren.  The group that has spent the most is the League of Conservation Voters, which opposes Brown's re-election.  (Associated Press)