Newly minted Republican Senate nominee Gabriel Gomez on Wednesday reaffirmed his refusal to sign a pledge his Democratic opponent has taken to curb the influence of third party ads.

"I’m taking one pledge and one pledge only: to protect and defend the Constitution. That’s the pledge I made when defending my country, that’s the pledge my mother and father made when they came here from Colombia, and that’s my pledge to the people of Massachusetts," Gomez said in a statement. During the Massachusetts Republican Senate primary, he also rejected the pledge.

The so-called "People's Pledge," Gomez refers to is an agreement that imposes financial penalties on candidates any time an outside group runs a TV, radio, Internet, or mail advertisement on their behalf. His Democratic opponent Rep. Edward J. Markey signed the agreement months ago. The language is based off a similar agreement Republican Scott Brown and now-Sen. Elizabeth Warren (D) each signed during the 2012 campaign.

"Gomez wants to be the next Scott Brown, yet refuses to sign the same pledge made famous by Senator Elizabeth Warren and Brown in 2012," said Democratic Senatorial Campaign Committee Executive Director Guy Cecil in a statement.

Without outside groups in the mix, Markey would have the early financial advantage. He has raised a lot more money than Gomez, who, notably, has shown a willingness to do some self-funding.

Markey said Wednesday that he plans to challenge Gomez "every single day" to take the pledge. He didn't rule out abandoning it if Gomez accepts outside support.