As Senate candidate Elizabeth Warren and U.S. Sen. Scott Brown struggle in the polls, the Brown campaign stressed Brown’s Democratic side to keep the incumbent Republican afloat in a primarily blue state.

Fighting for a state that, before Brown, last elected a Republican senator in 1972, the Brown campaign is pushing his bipartisan voting record and independent voice.

MassINC Polling Group’s polling data released in July showed Warren with 40 percent of the vote, a two-point lead that lies within the poll’s 4.4-percent margin of error.

But a Public Policy Polling poll conducted in August showed Brown with a 5-percent lead, with 49 percent of participants saying he is “an independent voice for Massachusetts.”

Another Kimball Political Consulting poll of 592 people conducted in August showed Brown with 49 percent of the potential vote, a 6 percent lead over Warren.

Just before Brown’s climb up in the polls, the Brown campaign stressed Brown’s democratic and independent voter appeal.

Brown’s campaign launched a new series of three TV ads in August entitled “Democrats for Brown,” each focusing on one of Brown’s Democratic endorsers.

The ads feature Democratic politicians who support Brown, including one featuring Former Bristol County District Attorney Paul Walsh.

Massachusetts Rep. Paul Casey, of Winchester, is the latest Democrat to join Brown’s endorsement list.

“We are very excited,” said Alleigh Marré, Brown’s press secretary in a phone interview. “It helps portray that Scott’s message is resonating across the aisle.”

Brown’s message, listening skills and accessibility are what made the mayor of Leominster, Dean Mazzarella, choose to endorse Scott Brown.

“I’ve been waiting for somebody like Scott Brown to come around for a long time, so it made it pretty easy to endorse him,” Mazzarella, an independent voter, said in a phone interview. “In my view, he has not taken party sides.”

Brown has garnered more than seven Democratic endorsements, including former Boston Mayor Ray Flynn and former Worcester Mayor Konnie Lukes.

The publicity surrounding Brown’s Democratic support stems from “the danger zone” he is in as he tries to break 50 percent in the polls, said Warren’s spokeswoman Julie Edwards in an email before the latest PPP poll.

In a state with only 11 percent of voters registered as Republican,  Brown will need more than his party to win, Edwards said.

“In Massachusetts, any Republican candidate must get significant Democratic and Independent support to win,” Edwards said. “In 2012, it is likely Scott Brown will need anywhere from 350,000 to 400,000 Obama voters to support him.”

Marré said Brown is “always going to be the underdog” in Massachusetts.

Brown only votes with Republicans 54 percent of the time in Washington and does a deal of work “across-the-aisle,” according to a Brown campaign press release.

But Brown’s history of giving tax breaks to the wealthy and voting against job creation in Massachusetts, combined with his campaign’s strategy to portray Brown as an independent, may not secure success, Massachusetts Democratic Party spokesman Matt House said in an email.

“Come November, voters won’t forget that he chose to stand with national Republicans instead of middle-class families,” House said.

That Republican stance includes subsidies for big oil, Edwards said.

But Marré said Brown is a “friend of motorists, not energy providers” and is working to keep gas prices low.

It is Warren, she said, who is destroying jobs and plans to raise taxes $3.4 trillion in the next 10 years.

The Warren campaign released a statement in August that said “phony attacks can’t hide [Brown’s] record for billionaires and Big Oil.”

Edwards said Brown has also received endorsements from conservative figures such as Mitt Romney, and said Brown’s re-election would give the Republicans the ability to enact their “extreme agenda” with “disastrous” results for Massachusetts families.

“Elizabeth has been out visiting cities and towns across the Commonwealth, meeting with voters and talking about her efforts to create a level playing field for working families,” Edwards said. “That’s what she’s going to keep doing each day from now until the election.”

This marks Brown’s first full campaign since he was chosen in a special election in 2010 to fill Democratic U.S. Sen. Ted Kennedy’s seat prior to his death.