BOSTON — Democratic U.S. Senate hopeful Edward Markey agreed Thursday to release his tax returns dating back to 2005, one more year than was previously released by his opponent Gabriel Gomez, in a day of campaigning in which money from outside groups was at issue as well.
Markey, a veteran U.S. congressman, will make public the tax returns Friday, according to spokesman Andrew Zucker, after strong pressure from Gomez and state Republican leaders to disclose the information.
Zucker also called on Gomez to release his own 2005 return, which could include additional details about a $281,000 deduction that Gomez took for promising not to alter his historic Cohasset home.
Markey and Gomez are competing in the June 25 special election for the Senate seat formerly held by U.S. Secretary of State John Kerry. The campaigns have sharpened their attacks in recent days, with the candidates or their surrogates calling each other out for misleading ads.
In another campaign development Thursday, a deep-pocketed outside environmental group that had spent nearly $900,000 during the Democratic primary said that it would back Markey in the election, though Markey publicly called on the group to stay out of the race.
Environmental activists led by California billionaire Thomas Steyer promised to return to Massachusetts to work against Gomez after spending nearly $900,000 in the Democratic primary that Markey won.
But Markey signed a so-called "People's Pledge" in the primary race that discouraged outside groups from buying advertisements, similar to an agreement between then-U.S. Sen. Scott Brown and Democrat Elizabeth Warren in last year's Senate race that Warren won.
Gomez declined to sign a pledge with Markey, leaving outside groups including NextGen free to spend on ads.
Chris Lehane, a spokesman for the NextGen Committee, said in a memo that the group planned to be a "politically disruptive force" between now and the election.
NextGen targeted a Markey opponent in the primary by focusing on his past support for the proposed Keystone XL Pipeline, which would run from western Canada to Texas. Critics contend it would carry "dirty oil" that contributes to global warming.
Gomez reiterated his support for the pipeline during an appearance Thursday before a local chamber of commerce group in Newton.
"The Keystone pipeline creates tens of thousands of jobs. It lowers our energy costs. It makes us less energy dependent around the world," Gomez said, adding that he considered himself a "green Republican" who believes human activity contributes to global warming.
Lehane said his group's strategy would include highly targeted paid media, with a focus on digital and online ads.
"From what little there is to know about Gomez, we've realized that he is simply a lightweight version of Mitt Romney — but without the experience," LeHane wrote in the memo, which was sent to Steyer's supporters in Massachusetts.
The candidates also agreed Thursday to a second debate sponsored by a Boston media consortium in the studios of WGBH-TV. It will be held June 18, exactly one week before the election.
The candidates have wrangled over debates in recent days, with both sides accusing each other of foot-dragging. They have agreed on only one other, a June 5 debate sponsored by WBZ-TV and The Boston Globe.
Gomez, a political newcomer, has called for four debates and accused Markey, a 36-year veteran of Congress, of trying to duck them.
But the Markey campaign says it has been stymied by the Gomez campaign in its attempts negotiate a debate schedule.
Associated Press writer Steve LeBlanc contributed to this report.