House Democrats entered 2009 with sky-high expectations but ended a roller-coaster year facing steady erosion in the polls with the bulk of their agenda piled up in the Senate.

Speaker Nancy Pelosi (D-Calif.) managed to pass the most ambitious agenda through the chamber in decades, marked by votes for the largest stimulus package in history, a massive cap-and-trade energy bill and a health care overhaul that would achieve near-universal coverage.

But Pelosi acknowledged that the Democrats have had a hard time marketing the laundry list of legislation that they’ve sent to the Senate.

“We’ve had a very challenging work year, and now we will message it to the American people,— Pelosi told CNBC’s chief Washington correspondent John Harwood in a Friday interview from Copenhagen. “It’s hard to bake the pie and sell the pie at the same time. We’ve baked the pie, now we’ll sell it.—

There’s a lot of selling to do. Voters favor Republican Congressional candidates over Democrats by an average of more than 2 points, according to a polling analysis by RealClearPolitics. And Congressional disapproval ratings stand at a whopping 66 percent — an alarming figure for the majority party.

“It feels like we’re limping out of here,— one senior Democratic aide said. But this aide saw brighter days ahead, with signs of an economic recovery sowing hope of a turnaround in the jobless rate by the time campaign season kicks into gear. And this source chalked up a bruising year to the necessity of moving a historically ambitious agenda. “There was an energy and an exuberance to address problems that have been festering for more than a decade,— he said. “Until you take the time to sell it, people don’t know it happened. You only need to look at how far the public mood has swung since the inauguration to know how quickly feelings can change.—

Pelosi, who described herself as “in campaign mode— last week, defended the size, scope and sequencing of the workload, which she said flowed from President Barack Obama’s aim to create jobs and reduce the deficit. “Some people said, ‘Oh, you’re doing too much,’— she said in a Wednesday roundtable with reporters in her Capitol office suite. “No, they’re all related. … We see it with an integrity, a oneness.—

“It’s a long time until Election Day,— another hopeful Democratic aide said.

Several aides said some of their struggles are due to the House having to tackle many of the toughest agenda items first with little cover from the president or help from the Senate.

“Almost every day we were fighting with one hand behind our back,— one House Democratic leadership aide said. “We weren’t entirely in sync with the White House and the Senate.—

The aide said that on health care, the House took the brunt of attacks from Republicans and their allies for months, while the president focused on the Senate Finance Committee and a failed effort to attract Republican support for a sweeping overhaul.

“We were being carpet bombed, whether it was the Republicans or all of their allies, whether it was energy or health care,— the aide said, adding that the administration failed to mobilize their base with Organizing for America to counter the Republican Party’s base, which became energized this summer with the Tea Party movement.

“We didn’t have our base involved this year, they checked out,— the aide said.

Republicans, meanwhile, have eyed the mountain of legislation that Democrats have sent over to the Senate, which includes a financial regulation package, a new government-run student loan program and hundreds of other bills, as a sign of overreach, not a lack of salesmanship.

The race to get the House out of town in time for Pelosi to get on a jet to Copenhagen last week typified much of the year for House Democrats.

From the first weeks of Obama’s presidency, when the House was in a sprint to finish the $787 billion stimulus package, House Democrats were the “stepchild— of the administration, taken for granted and repeatedly thrown “under the bus,— the Democratic leadership aide said.

In the final week, a $150 billion jobs bill and a $290 billion debt limit increase were forced off of the Defense spending bill with the administration and the Senate focused on the health care bill, forcing a mad scramble to whip votes of Members on the suddenly stand-alone measures.

Some Democrats also point to the climate change bill as a pivotal moment for the party. Pelosi’s signature initiative came before health care — to the chagrin of some powerful Members, including the party’s campaign chief, Democratic Congressional Campaign Committee Chairman Chris Van Hollen (Md.), and Ways and Means Chairman Charlie Rangel (D-N.Y.) and the bulk of the party’s conservative wing.

Early grumbling became a load roar of discontent after Members went home after the vote and were pummeled by opponents with not much more than a peep from supporters.

“This is going to be one of those debates that we’ll be looking at at the end of next year’s elections,— the Democratic aide said. “How much did it delay us from really sinking our teeth into health care? What was the psychological impact on Blue Dogs?—

But the aide insisted that despite the year’s hiccups, Democrats will be able to paint Republicans into a corner.

“As we clear the decks, they are going to have a hard time explaining why not only did they oppose everything that we did, they were supporting the status quo and the special interests and proposing the same things that got us into this mess in the first place,— the aide said. “That’s going to play very well for us heading into an election year where people are very angry and trying to figure out who to be angry at.—

The aide also said the president has to play a more forceful role in taking it to the Republicans and defending his agenda.

“They cannot be worried about getting their hands dirty, from the administration on down,— the aide said. “When they punch, we need to punch back harder, and that starts at the top.—