SPRINGFIELD, Mass. (AP) — President Barack Obama is heading to Boston to rally supporters of Democratic U.S. Senate hopeful Edward Markey a day after Markey and Republican Gabriel Gomez squared off in their second debate.

Despite a more muted tone, the two candidates still clashed Tuesday on everything from tax policy to the National Security Agency's collection of billions of Americans' phone and Internet records.

Gomez said Edward Snowden, the former intelligence contractor who claimed responsibility for revealing the surveillance programs, should be held accountable.

"Is Snowden a hero or a traitor? I think it's going to be determined after we find out more facts," Gomez said. "But if his information ... puts anybody at risk, he's by far not a hero. He is a traitor."

Markey said Snowden should accept responsibility, but added that Americans shouldn't have to choose between security and privacy.

"We have to make sure that we have in place the privacy protections so that as law enforcement officials are looking for the guilty needle that there is not a compromise of the innocent haystack of e-mails and phone calls that all Americans are making," Markey said.

Markey also seized on Gomez's apparent willingness to leave open the possibility of eliminating the federal home mortgage deduction to help close the deficit.

Gomez said while he hoped the deduction would stay, "going into anything with preconditions almost guarantees failure."

"I do have a precondition," Markey responded. "And it is that home mortgage deduction should not be on the table. People should be able to afford the home of their dreams."

Both candidates said they support a $10 federal minimum wage, but Gomez said the larger goal should be to help Americans aim even higher.

"People don't want to earn just $10 an hour," the former Navy SEAL said. "They want a chance at the American Dream."

Markey said that for many Americans, winning a $10 an hour minimum wage is a first step. He also said the nation should end tax breaks for oil companies and other corporations.

"Subsidizing the oil industry is like subsidizing a fish to swim and a bird to fly," Markey said. "You simply don't have to do it."

Gomez said he supports closing tax loopholes and lowering the federal corporate tax rate to encourage companies to bring more of their money into the country to be taxed.

Gomez also said taxpayers "should also be able to do our own taxes in a simple, efficient way."

The two again sparred on gun control.

Gomez said that he was "ashamed" only four Republicans voted for a Senate bill that called for wider gun background checks. Markey criticized Gomez for not also supporting a federal assault weapons ban.

In one of the evening's sharper exchanges Gomez criticized Markey for mentioning the Newtown, Conn., school shooting in a television ad that faulted Gomez for not supporting a ban on high capacity magazine clips.

"To think that you are the only political candidate to actually invoke the Newtown massacre for political gain is beyond disgusting," Gomez said.

"Mr. Gomez thinks that when we talk about the differences between the two of us on very important issues, that somehow or other we are engaging in negative politics," Markey said. "We are not."

The two were also asked what they could do to help improve the economy in western Massachusetts. The unemployment rate in Springfield tops 10 percent, much higher than the state as a whole.

Gomez said one way to protect local jobs is to repeal the medical device tax in Obama's 2010 federal health care law. Markey said he supported job-creating projects like the Union Station project in Springfield.

Both Markey and Gomez said they would support changes in Senate rules that allow even a single lawmaker to block legislation.

"We need to make sure these big issues get the debate they deserve," said Markey.

Gomez said the filibuster can be an effective tool. Referring to a recent 12-hour filibuster, Gomez added: "I could go a lot longer than that without having to go to the bathroom," citing his Navy SEAL experience.

Asked if they would support changes to federal marijuana laws, Markey said he supported the Massachusetts ballot question allowing the medicinal use of marijuana. Gomez said the question should be left to the states, but he would personally not support anything beyond the medicinal use of marijuana.

Tuesday's debate was sponsored by a Springfield media consortium and took place in the studios of WGBY-TV.

Also Tuesday, Vice President Joe Biden attended a joint fundraiser for Markey and the Massachusetts State Democratic Party in Washington hosted by former Vice President Al Gore and Vicki Kennedy. Markey's campaign would not say how much money they expected to raise.

Gomez issued an open letter to Obama, who is visiting Boston's Roxbury neighborhood on Wednesday, saying that if he is elected to the Senate he would work with Obama to represent all Massachusetts residents.

"Where we disagree," he wrote, "I will reach across the aisle and work to find common ground with you, and with my fellow members of Congress."

He said it is "time for a bipartisan problem solver who will put people before politics."

The election is June 25.