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.

While the two toned down their attacks, they still clashed Tuesday night in Springfield on everything from tax policy to the National Security Agency's collection of billions of Americans' phone and Internet records.

Both said Edward Snowden, the former intelligence contractor who claimed responsibility for revealing the surveillance programs, should be held accountable, but Markey also said Americans shouldn't have to choose between security and privacy.

Both said they support a $10 federal minimum wage, but Gomez said the goal should be to help Americans aim higher. Markey said for many, a $10 minimum wage is a first step.