BOSTON Outside groups have poured more than $4.5 million into the hotly contested race for Congress between incumbent Democratic U.S. Rep. John Tierney and Republican challenger Richard Tisei.
The most recent Federal Election Commission records show the independent expenditures total more than the combined amount of campaign cash raised by the 6th Congressional District candidates themselves.
There have been more independent expenditures in the Tierney-Tisei race than in any U.S. House race in New England.
Republicans view Tierney, a Salem Democrat who is seeking an eighth term, as the most vulnerable of the incumbent Democratic House members seeking re-election in Massachusetts.
According to the FEC records, Tisei, an openly gay former state senator and 2010 Republican nominee for lieutenant governor, has been the beneficiary of about three-quarters of the spending by outside groups in the campaign.