Sen. Jeanne ShaheenCynthia (Jeanne) Jeanne ShaheenJudd Gregg: 'Medicare for all' means rationing for everyone The Hill's Morning Report - Sponsored by CVS Health - A pivotal day for House Republicans on immigration Overnight Defense: Senate confirms Haspel as CIA chief | Trump offers Kim 'protections' if he gives up nukes | Dem amendments target Trump military parade MORE (D-N.H.) is using former Sen. Scott Brown's (R-Mass.) words against him in her first radio ad of the cycle. 

The New Hampshire Democrat is hammering her potential GOP opponent for his refusal to sign a pledge to keep super-PACs out of the race. The ad is the campaign’s latest attempt to knock Brown’s newfound opposition to the agreement known as the People’s Pledge, a contract he created in his race against Sen. Elizabeth Warren (D-Mass.) that prevented outside groups from airing attack ads on TV and radio.

Shaheen called for Brown to sign the same pledge in their race, just days after he launched his exploratory committee in New Hampshire, but Brown has refused. The new radio ad uses a clip from one of Brown’s Massachusetts Senate campaign ads to highlight his previous support for the pledge.

“You’ve probably heard about the super-PACs that have been created to influence elections, usually with negative ads,” Brown says in the clip. “So, I did something about it in my own race. I proposed and signed a pledge to stop third-party groups from coming into our state.”

A narrator goes on to note that “now Scott Brown won’t sign his own pledge to stop them. Maybe it’s because Big Oil and Wall Street want to buy him a Senate seat.”

The ad implores listeners to tell Brown to sign the pledge.

“It was the right thing to do in Massachusetts, and it’s the right thing to do here. New Hampshire deserves a clean election, too,” it closes.

Shaheen's campaign is spending five figures to air the ad statewide.

In response, Brown charged that Shaheen's focus on the pledge shows how "out of touch" she is with New Hampshire.

"It's disappointing that Senator Shaheen's first ad of the campaign is a negative ad attacking me," Brown said in a statement.

"When I talk to the people of New Hampshire, they tell me they are concerned about health care, jobs, America's standing in the world and how we can control our debt. Those are the issues I am focused on. Senator Shaheen's negative ads are a sad commentary on just how out of touch she is with the things people care about."

Shaheen has already been the target of more than a $1.5 million in attack ads from GOP outside groups, nearly a third of that from Americans for Prosperity (AFP), which is backed by conservative billionaires Charles and David Koch. Their ads have largely focused on ObamaCare, and Democrats admit they will be outspent on air if AFP and other Republican groups keep up their current pace.

And the ObamaCare attacks — and efforts to tie her to President Obama — could take a toll on Shaheen in New Hampshire, where the law and the president both remain unpopular. The New Hampshire GOP launched a Web video on Monday to that effect, tying her to Obama and highlighting a clip where Shaheen demurred when asked whether she'd like him to campaign for her in the state.

Democrats believe if Brown signs the People’s Pledge, they’ll have a more level playing field with just the candidates airing TV and radio ads, though Brown is still expected to match, if not surpass, Shaheen’s fundraising for the race.

While Shaheen remains popular in New Hampshire, Republicans believe they have a shot at taking her down with Brown in the race and the national political climate working against Democrats.

— This piece was updated at 10:15 a.m. to reflect comment from Brown and the NHGOP.