Republicans will maintain majority in the U.S. House of Representatives, CNN projects.
Going into the election, Republicans control the House by 242-193. Though all 435 members faced voters on Tuesday, control of the chamber rested on some 50 to 60 races that were considered competitive, some of them because of redistricting.
The number of swing districts has shrunk in recent years as GOP legislatures have shored up their seats and Democratic-led state houses have strengthened their party's districts.
Democrats needed to pick up 25 Republican seats to regain control.
Minority Leader Rep. Nancy Pelosi and other Democrats noted that 58 Republicans represent districts won by Obama in 2008; they pointed to those wins as a template to a successful election night, but by shortly after 9 p.m., CNN projected that they would not achieve their goal.
Speaker John Boehner told CNN on Sunday that the GOP "might" pick up more seats in the House.
"I feel pretty good about at least maintaining the numbers that we have," Boehner said. "After winning 65 seats from the Democrats in the 2010 cycle, and all the experts been talking about how many seats we're going to lose -- five, 10, 15 -- but I never bought into the idea that we had to lose any seats."
David Wasserman, who analyzes House races for the Cook Political Report, said Democrats were waging competitive campaigns in just 32 of those districts -- not enough to regain control of the House.
Stuart Rothenberg, an independent campaign analyst, projected last week that Democrats will gain two to eight seats.
A senior House GOP campaign official predicted last week to CNN that Republicans would gain four to six seats.
The battleground for many of these House races has tilted increasingly toward the Northeast and the Midwest, after a number of moderate Democrats lost in Southern districts in the 2010 midterms.
In Illinois, Democrats see opportunities to defeat tea party freshman Rep. Joe Walsh, seven-term Rep. Judy Biggert and a moderate Republican freshman, Rep. Bob Dold.
Democrats have also set their sights on freshmen Reps. Nan Hayworth, Chris Gibson, Ann Marie Buerkle, and Michael Grimm in New York.
Democratic campaign officials say they can 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.
Two years after the tea party helped Republicans seize control of the House, it has faded as a factor.
House Republican candidates are 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 are "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, have 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 have 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 last 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, compiled by Adam Levy and Robert Yoon, CNN Political Research:
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 is Ann Kirkpatrick, who was elected in 2008 and was swept out in the Republican wave two years later. The Republican nominee is Jonathan Paton, a former state senator. Kirkpatrick has a sizeable fundraising advantage over Paton, but national Republicans have invested heavily to help close the gap in TV ads. This seat is 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 is Republican Martha McSally, a retired Air Force colonel and combat pilot. Barber had a financial advantage at the start of October though McSally has remained competitive on the airwaves. Still, Barber is expected to win.
Arizona 9: Kyrsten Sinema (D) vs. Vernon Parker (R)