Democratic campaign officials predicted they could upset several GOP incumbents in California.
But California Rep. Xavier Becerra, one of Pelosi's top lieutenants, acknowledged, "We'd need a wind" to get the kind of gains that would put Democrats back in control.
Tea party fades as 2012 factor
Two years after the tea party helped Republicans seize control of the House, it had faded as a factor.
House Republican candidates were still stressing the core issues that the tea party movement pushed in 2010 -- less government and a focus on cutting federal spending and the deficit -- but Republican candidates were "not wearing the tea party label on their sleeves," one senior GOP strategist working on House races said recently.
Democrats, bolstered by polling that shows that many voters blame the tea party for gridlock in Washington, had tried to try to pin the label on virtually every Republican incumbent and challenger.
The "Tea Party Republican Congress has a 13% approval rating," House Democrats' campaign chief Rep. Steve Israel of New York told reporters last month. He said Democrats had a chance to regain the majority because "there is a deep sense of buyer's remorse spreading throughout this country."
With the bulk of this cycle's competitive races concentrated in districts represented by more moderate members of each party, the outcome of this election could mean an even more polarized House in 2013.
The GOP conference could include more conservatives and fewer moderate Democrats, whose ranks were decimated in 2010. That could tilt the Democratic caucus leftward.
A recent study by the Cook Political Report found that the number of swing districts in the nation dropped from 164 to 99 over the past 14 years. That decline has widened the ideological divide between the two parties.
"There's a remarkable reduction in the number of members who have an incentive to compromise," Wasserman told CNN.
Key House race snapshots
Arizona 1: Jonathan Paton (R) vs. Former Rep. Ann Kirkpatrick (D)
Open Republican-held seat
This redrawn district covers most of northern and eastern Arizona. The Democratic nominee was Ann Kirkpatrick, who was elected in 2008 and was swept out in the Republican wave two years later. The Republican nominee was Jonathan Paton, a former state senator. Kirkpatrick had a sizable fundraising advantage over Paton, but national Republicans invested heavily to help close the gap in TV ads. This seat was a top priority for both parties.
Arizona 2: Rep. Ron Barber (D) vs. Martha McSally (R)
Democrat Gabrielle Giffords would have run here had she sought a fourth term. Giffords is recovering after being shot in January 2011 in Arizona. Her district director Ron Barber, who was also wounded, won a special election to fill her seat when she resigned last January. His opponent was Republican Martha McSally, a retired Air Force colonel and combat pilot. Barber had a financial advantage at the start of October though McSally remained competitive on the airwaves. Still, Barber was expected to win.
Arizona 9: Kyrsten Sinema (D) vs. Vernon Parker (R)
The battle for this new district pitted Democrat Kyrsten Sinema, a former state senator, against Republican Vernon Parker, the former mayor of Paradise Valley. Both parties invested heavily in the race, though a Democratic super PAC tipped the TV ad war balance of power slightly in the Democrat's favor.