Liberal House Democrats on Tuesday applauded President Barack Obama and Vice President Joseph Biden for getting tough with the Democratic base about playing a bigger role in the midterm elections.

“Sometimes we just have to be straightforward,” said Rep. Mike Honda (D-Calif.), a leading voice in the Congressional Progressive Caucus, which represents more than 80 liberal House Democrats.

Obama comes down hard on liberals in a Rolling Stone magazine interview due out Friday. He calls it “irresponsible” that some supporters “are sitting on their hands complaining” ahead of the elections as opposed to helping build enthusiasm for the party’s accomplishments in Congress.

“People need to shake off this lethargy; people need to buck up. … If people now want to take their ball and go home, that tells me folks weren’t serious in the first place. If you’re serious, now’s exactly the time that people have to step up,” Obama said.

Biden is echoing Obama’s message, although he was more blunt at a New Hampshire campaign event Monday: Democrats need to “remind our base constituency to stop whining and get out there and look at the alternatives. This president has done an incredible job. He’s kept his promises,” he said.

Liberal groups quickly seized on Biden’s comments and used the moment to criticize the White House for failing to deliver on some of their top priorities, such as a public option in health care reform and breaking up big banks in financial reform.

“The ‘professional left’ is busting our butt to mobilize progressive voters in 2010, picking up the ball that this White House dropped when they refused to fight for the overwhelmingly popular public option, refused to break up the big banks and demobilized Obama voters who expected this president to at least fight for big change,” said Adam Green, co-founder of the Progressive Change Campaign Committee.

The White House has been ramping up its campaigning in recent weeks to try to stem expected Democratic losses in November. Republicans are hoping to pick up the 39 seats they need to take over the House and the 10 seats they need to win back the Senate. One of the biggest challenges for Democrats is rivaling the level of enthusiasm the tea party movement has injected into GOP races.

While Obama’s new bent toward liberals is turning some people off, many liberal Members on Capitol Hill welcomed it.

“We’ve done the heavy lifting and we’ve done it ourselves,” Honda said. “Straight talk sometimes gets their attention.”

Congressional Progressive Caucus Co-Chairwoman Lynn Woolsey said Obama and Biden have been doing “a good job of rallying the base” when they focus on the elections being about a choice between the parties. But millions of Americans are still frustrated that they did not get all the change they wanted, the California Democrat said, which should not be confused with whining.

“They are representing the concerns of the voters we need to return to the polls in November so that a Democratic Congress can continue to push for the change they voted for two years ago,” she said.

Still, CPC Co-Chairman Raúl Grijalva cautioned against chiding liberals too much since they “have been the backbone for much of the legislation” that has advanced in Congress. That said, the fact that the president has stepped up his campaigning in the past two weeks has been “the most helpful of anything that’s been done” for Democrats, the Arizona Democrat said.

Several senior Democratic aides said Obama’s and Biden’s sentiments reflect the feelings of many Members who fear the base is not coming through for them after they took tough votes on measures liberals wanted and supported.

“I don’t think leadership has publicly used these sorts of words in calling out the progressive community. But the president is voicing frustrations that a number of Members feel, including Democratic leaders,” one senior Democratic aide said.

“They are clearly just trying to speak plainly and fire people up. I am OK with that,” another House Democratic aide said.

A Senate Democratic leadership aide said it is important to note that Obama’s and Biden’s criticisms are not necessarily directed at all voters, or even loyal Democrats.

“They are meant for the subset of liberal activists who like to make the perfect the enemy of the good and would rather make an enemy of a friendly administration rather than confront the Republican obstructionists who are the ones blocking reform,” the aide said.

House Majority Leader Steny Hoyer (D-Md.) appeared to side step a question Tuesday about whether going after liberals is an effective way to get Democrats to the polls.

“I think the base is getting more and more energized every day when they see, as [former] Sen. Biden said, ‘As long as you’re running against the almighty, you’re going to lose. When you run against the alternative, we’re going to win,’” Hoyer said during a sit-down with reporters.

GOP leaders have already been trying to seize on the intraparty scuffle and frame the issue as Obama blaming Americans for Democrats’ electoral prospects. The Senate Republican Conference sent around a document Tuesday that said Obama’s and Biden’s criticisms reflect a new strategy of blaming “lethargic” and “whining” voters for their shortcomings.

But a senior House Democratic aide dismissed the idea that such a message would gain any traction.

“That’s just ridiculous,” the aide said.