

Democratic presidential candidates, from left, Bernie Sanders, Martin O'Malley, Hillary Rodham Clinton and Lincoln Chafee stand on stage during the Iowa Democratic Party's Hall of Fame Dinner, July 17 in Cedar Rapids, Iowa. (AP Photo/Charlie Neibergall)

The campaign of presidential hopeful Martin O’Malley has made several unsuccessful overtures to rival Bernie Sanders’s camp in recent weeks to jointly buck the Democratic National Committee’s schedule of six debates.

In private conversations, confirmed by aides to both candidates, O’Malley representatives have suggested that both Sanders and O’Malley agree to accept invitations to debates not sanctioned by the DNC in a bid to open up the process, which O’Malley last week characterized as being “rigged” to limit the exposure of front-runner Hillary Rodham Clinton.

The DNC has threatened to exclude candidates from its debates if they take part in a non-sanctioned gathering. But aides to O’Malley, the former Maryland governor, say they are skeptical of the threat, particularly if Sanders and O’Malley stand up together against the DNC.

[O’Malley blasts Democratic leaders for ‘rigged’ 2016 debate process]

Though Sanders, an independent senator from Vermont, has been vocal about wanting more debates, aides say his campaign is more reticent to cross the DNC, reasoning that a chance to appear with O'Malley and other lower-polling Democrats is not worth the risk of losing his shots on stage with Clinton.

Recent polling has shown Sanders with an apparent lead over Clinton in New Hampshire and closing in on her in Iowa. O'Malley remains mired in the single digits in both early nominating states.

"At the end of the day, I do want to be on the stage with Hillary Clinton," Sanders said in an interview last week.

Sanders spokesman Michael Briggs said Thursday that the campaign’s thinking has not changed in recent days, emphasizing that Sanders would like there to be more debates in which all the Democratic candidates participate

[Sanders to Democratic Party elite: Consider me, not Hillary Clinton]

Briggs said Sanders would also like to debate Republican candidates, a dynamic that could highlight differences between the competing agendas of the major parties without running afoul of DNC debate rules.

O’Malley aides suggest that if both O'Malley and Sanders agree to take part in other debates, it is unlikely that Clinton would skip the gathering.

DNC officials defend the debate schedule as a sufficient opportunity to size up candidates against one another, noting that multiple groups will also be hosting less formal forums. Critics of the schedule note that only four of the six debates are scheduled to occur before the Iowa caucuses.

On Thursday, DNC Chairwoman Debbie Wasserman Schultz declined to answer several questions from reporters on the subject following a meeting she hosted between Vice President Biden and prominent Jewish activists and Democratic donors at a Jewish community center in Davie, Fla.

She said she was appearing there only in her role as a Florida congresswoman.

O’Malley aides say they have also been heartened by what appears to be growing pressure on the DNC from a variety of sources to open up the schedule. A grass-roots group, for example, has been formed to pressure the party for more debates and plans a demonstration later this month outside DNC headquarters in Washington.

[O’Malley forwards a ‘flattering’ Clinton e-mail in an attempt to make a point]

O'Malley has made the cry for more debates part of his pitch on the campaign trail for a few weeks now. During an appearance in Hollis, N.H., last week, for example, he told his audience at a house party that Democratic debates would be an effective way to advance issues important to the middle class that are getting drowned out by all the media attention on the Republicans.

"What is our message in the Democratic party?" O'Malley said. "It seems our brand is what did Hillary Clinton know about her e-mails and when did she know it, and did she wipe her server or did she not?"

Sanders has been seeking to work cooperatively with the DNC on another front: by developing a joint fundraising agreement under which he will help the party raise money for use in the generation election campaign regardless of who the Democratic nominee is.

Clinton has already signed such an agreement, and Sanders's aides said they are close to doing so. O'Malley, meanwhile, recently said in New Hampshire that his signing such an agreement would be putting "the cart before the horse."

"I am not the candidate of big Wall Street money," O'Malley said. "So I have to put all of my effort and fundraising efforts into getting my message across in the primary, in this critically early state of New Hampshire and also her sister state of Iowa. So that’s what I’m going to be doing."

Staff writer Ed O'Keefe contributed to this report.