A key part of House Democrats' strategy is to target more than a dozen so-called "orphan districts" -- congressional seats in states where the presidential campaign is not active and where Obama is expected to carry the state handily.
For example, Democrats are trying hard to unseat GOP incumbents in California, New York, and Obama's home state of Illinois.
GOP incumbents in those states can't count on momentum from the presidential ticket, and high turnout for Obama works against them.
Right after Republicans took control in 2010, House Speaker John Boehner recognized this weak spot and focused a major effort to support the mostly GOP freshmen in these states. Boehner has personally raised more than $10 million to help build local organizations and traveled extensively to stump for these candidates.
Back in April he raised the prospect of potentially significant losses in orphan districts, his remarks intended to warn Republicans focused on the presidential race and the battle for the Senate not to take GOP control of the House for granted.
The battleground for many of these House races has tilted increasingly toward the northeast and Midwest, after so many 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.
Former President Bill Clinton held a rally on Sunday in New York for Sean Patrick Maloney, his former aide who is running against Hayworth. He also recently held an event for five California Democrats, another area where campaign officials argue they can upset several GOP incumbents.
California Rep. Xavier Becerra, one of Pelosi's top lieutenants, told CNN a combination of wins in orphan districts, combined with pickups sprinkled around the country could translate into a path to the majority.
But even Becerra conceded, "we'd need a wind" to get those kind of gains. With a bitterly contested presidential election in 2012 that's expected to be close it's not the political environment for any kind of wave election.
Because the GOP picked up 63 seats in the 2010 midterms the bulk of their efforts are geared toward protecting incumbents. But there are several places where Republican challengers are on the offense.
Rep. Pete Sessions, chairman of the National Republican Congressional Committee, noted on CNN's "Starting Point" last week several places where he believes his party can topple some veteran Democratic members, like Rep. Jim Matheson, D-Utah, Rep. Tim Bishop, D-New York, and Rep. John Tierney, D-Massachusetts.
"We have an African-American, as matter of fact, Haitian-American candidate in Utah that's doing a great job. We have a guy, Randy Altschuler, downtown literally in New York, New York City, out on the island, probably is going to win his race. We have Richard Tisei in Massachusetts, a man who's going to win, a Republican in Massachusetts," Sessions said.
Senior GOP officials also point out that they have put traditionally blue seats in Rhode Island and Connecticut in play this cycle, forcing Democrats to spend their own resources defeding those districts.
North Carolina moderate Democrats Larry Kissel and Mike McIntyre, who both survived the GOP tsunami in 2010, are battling strong challenges.
Two years after tea party fuels GOP win, fades as 2010 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 as one senior GOP strategist working on House races explained, they are "not wearing the tea party label on their sleeves."
Democrats, bolstered by polling that shows that many voters blame the tea party as the reason for gridlock in Washington, continue to try to pin the label on virtually every Republican incumbent and challenger.
House Democrats' campaign chief Rep. Steve Israel, D-New York, argued to reporters last month that the "Tea Party Republican Congress has a 13% approval rating," and maintained Democrats have a chance to regain the majority because "there is a deep sense of buyer's remorse spreading throughout this country."
Even in a solidly blue state like Massachusetts, Democrats are trying to brand Tisei, who already said he would break with his party on taxes, as a tea party Republican.
Democrats say control could hinge on unease over Wisconsin Representative and vice presidential nominee Paul Ryan's Medicare plan.
Pelosi insists that Romney's pick of Ryan as his running mate was the game-changing moment in the battle for the House.
"Mark your calendar, August 11th, the day he was chosen gave a clarification to the issue of Medicare," Pelosi said about Ryan on CNN earlier this month. "This is a person who has been the destroyer of Medicare guarantee," she added.
Democrats had already been highlighting the Ryan Medicare proposal across the country, but they believe that giving it national prominence helped make their case that the dramatic overhaul the House Budget Committee chairman proposed would prove too alarming to voters.