President Obama’s communications czar sought to soothe frustrated liberals Friday, telling them Obama needs their support to win reelection.

White House communications director Dan Pfeiffer faced a grilling during an appearance at the Netroots Nation conference, a gathering of liberal bloggers and activists meeting this year in Minneapolis.

{mosads}Pfeiffer faced tough questions from Kaili Joy Gray, an associate editor for the liberal blog Daily Kos, who often reacted to the communications director’s answers to questions with an audible sigh or a skeptical, elongated “OK.” 

“Frankly, we’re all a little sick of hearing about that one,” Gray said of Pfeiffer’s mentions of the Lilly Ledbetter Fair Pay Act. Hecklers sometimes interjected during the Q&A, voicing their skepticism toward Pfeiffer and accusing him of being evasive in his answers.

Pfeiffer admitted that the administration has been “frustrated” with its critics on the left, but pleaded for their support heading into 2012.

“We can either work together and finish that work that we started in 2008 or we can be relegated back to the sidelines and see what a Republican president … does to this country,” he said at the event, which was streamed online.

Pfeiffer said that Obama is “absolutely” counting on his liberal base to turn out in 2012. 

Asked about the Q&A at a briefing on Friday afternoon, White House press secretary Jay Carney called it “a useful and robust conversation.” 

Carney downplayed the attitude of the audience. 

“I would not characterize it as discontent,” Carney said. “There were a lot of things Dan [Pfeiffer] talked about in that engagement that obviously met with approval in that room and broadly beyond that.” 

Carney said that having people pressing the administration on “more to be done” was “the nature of our public life here.”

It’s no secret that liberals have been frustrated with the Obama White House, which has differed with the left on a host of foreign policy and economic issues.

The administration also has sometimes been frustrated with its liberal supporters. 

This friction was perhaps best reflected in former press secretary Robert Gibbs’s criticism of the “professional left” in an interview with The Hill last year. The comments sparked outrage from progressive activists who saw the phrase as derogatory. 

“Sometimes when our friends attack us, we get frustrated,” Pfeiffer said of the White House’s relationship with the left.

“I also know that beyond that, without a lot of the people in this room today, Barack Obama would not be president of the United States,” he said at the outset of the program.

Obama needs the support of liberal groups in what is shaping up to be a tight election in 2012. The president needs to bring out his base while holding on to a majority of Independent voters. He won the Independent vote in 2008, but polls suggest those voters moved to Republicans in last year’s congressional elections. 

Obama has courted the business community and Independent voters since Democrats were swept from their House majority last fall. He reached a deal with Republicans in December that extended Bush-era tax rates, disappointing liberals who wanted him to stick to a campaign promise to end those tax rates for wealthier taxpayers. 

Obama has also agreed to spending cuts, some of which disappointed the left, and is pursuing congressional action on three free-trade deals that are opposed by organized labor. 

On foreign policy, Obama is winding down wars with Iraq and Afghanistan, but he first ordered more troops into the latter country and has also launched a military action against Libya that liberal Rep. Dennis Kucinich (D-Ohio) decries as illegal.

The president did win a victory for the left at the end of last year by convincing the Senate to approve a measure ending the military’s ban on gays and lesbians serving openly in the military.

A Gallup poll released Friday found Obama trailing a general GOP presidential candidate. Forty-four percent of registered voters said they would elect a Republican candidate next fall, while 39 percent said they would reelect Obama. Eighteen percent expressed no opinion.

Obama fared better in a different poll earlier this week that matched him against specific GOP candidats.

An NBC News/Wall Street Journal poll found that former Massachusetts Gov. Mitt Romney (R) would lose, 49-43 percent, to Obama, while the president would best former Minnesota Gov. Tim Pawlenty (R), 50 percent to 37.

—This story was posted at 11:07 a.m. and last updated at 2:14 p.m.