Updated

Massachusetts Republican U.S. Senate hopeful Gabriel Gomez donated to President Barack Obama's campaign during the 2008 election cycle. But Obama is not thanking him for the cash.

Instead, on Wednesday Obama is scheduled to visit Boston to attend a rally for Gomez’s Democrat challenger, Edward Markey, in the city's Roxbury neighborhood. The President is the latest and biggest weapon the Democrats are dispatching in a lineup of political heavyweights to Massachusetts, backed by a river of outside money, to head off the possibility of an upset by Gomez.

National Republican groups have been reluctant to devote resources to a race that many Washington-based strategists have thought unwinnable for the GOP.

Few GOP stars or organizations have been willing to help Gomez, who acknowledged having donated to Obama during the 2008 election cycle.

Yet both parties know special elections draw far fewer voters — and they remember the special election in 2010 that ended with a Republican winning the Senate seat long-held by the late Edward M. Kennedy.

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

— Gabriel Gomez, Republican U.S. Senate Candidate

And Democrats, already down one Senate seat with the death this week of Sen. Frank Lautenberg of New Jersey, don't want to appear complacent even as polls suggest a likely victory when voters cast ballots in two weeks.

Second Debate

Despite the more muted tone on Tuesday, the two still clashed 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 toward that dream. 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 corporate and personal tax loopholes, and backs 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 "a lot of people in my party are wrong on gun control," and that he was "ashamed" only four Republicans voted for a Senate bill that called for wider gun background checks. Markey said the background checks were only a start. He criticized Gomez for not supporting a federal assault weapons ban.

In one of the evening's sharper exchanges Gomez said it was "beyond disgusting" that Markey raised 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.

Markey responded by saying, "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. We are not."

Markey and Gomez also split on the proposed Keystone XL Pipeline, which would bring oil from western Canada to Texas.

Gomez said the project would create jobs, while Markey said the United States would end up bearing all the environmental risk while the oil itself is dumped onto the international market.

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 included in President Barack Obama's 2010 federal health care law.

Markey said he supported job-creating projects in western Massachusetts including the Union Station regional transportation 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 if used properly. 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 ballot question in Massachusetts allowing the medicinal use of marijuana.

Gomez said the question should be left to states instead of the federal government, but he would personally not support anything beyond the medicinal use of marijuana.

Tuesday's debate was sponsored by a consortium of Springfield media outlets and took place in the studios of WGBY-TV. It took place a day after a Suffolk University poll showed Markey has the backing of 48 percent of voters compared with 41 percent for Gomez.

Unfazed By Big Spending

Republicans believe there's an outside chance that they can again eke out a victory over a Democrat in the liberal-leaning state.

Both sides expect a flood of new advertising in the coming days. So far, Democrats have outspent Republicans roughly $2 million to $1.5 million, according to officials who track political advertising. The Senate Democrats' campaign arm has reserved another $750,000 for statewide television ads to help Markey, while the Democratic-aligned Senate Majority PAC planned to invest another $700,000 in the final weeks. The League of Conservation Voters also has pledged to spend $400,000 on mailings to benefit the Democratic nominee.

Gomez said Friday he's unfazed by the spending.

The decisions "to flood Massachusetts with more dirty, negative attacks prove that national Democrats are now in a full-fledged panic," he said.

Gomez has relied on the Massachusetts Republican Party to help pay for his television ads.

The spending disparity aside, the uncertainty of off-year special elections and the lessons of Brown's 2010 victory loom large for Republicans and Democrats alike.

"Democrats are confident, but we're taking nothing for granted," said Matt Canter, the deputy executive director of Senate Democrats' national campaign arm.

More than Democratic pride is at stake. Democrats narrowly control the Senate, and party officials acknowledge that Obama can't afford to lose another reliably liberal vote when he has big-ticket legislative priorities on his plate. Upcoming votes on immigration and the budget could come down to just a few votes.

After Lautenberg's death, New Jersey Gov. Chris Christie tapped a fellow Republican to fill the seat until a special election in October.

A final debate is scheduled for June 18.

The election is June 25.

Based on reporting by the Associated Press.

Follow us on twitter.com/foxnewslatino
Like us at facebook.com/foxnewslatino