Throughout the GOP primary, the conservative wing of the House Republican Conference made clear its reluctance to embrace Romney and its doubts about his conservative credentials and ability to draw a contrast with Obama.

But Sessions noted that Romney's presence on the ticket would be a particular advantage for Republicans running in the Northeast. He added that GOP candidates from every corner of the country are in line with Romney's forward-looking vision on the economy, spending and job creation.

"One hundred percent of Republican candidates for the House will be pleased and energized by Mitt Romney," he said at a breakfast hosted by the Christian Science Monitor.

Democrats said Romney would be a liability for Republicans running for Congress on the same ballot, arguing that his personal finances would send the wrong signal to middle-class voters.

"This Tea Party Republican Congress' record low approval ratings mean that it's Mitt Romney who can’t afford to be tied to their extremism, their expanding corruption scandals and their priorities that protect millionaires and not the middle class," said Democratic Congressional Campaign Committee spokesman Jesse Ferguson.

Asked about House Speaker John BoehnerJohn Andrew BoehnerFormer top Treasury official to head private equity group GOP strategist Steve Schmidt denounces party, will vote for Democrats Zeal, this time from the center MORE's (R-Ohio) comments in April that Republicans stand a one-third chance of losing their majority in the House, Sessions and NRCC Deputy Chairman Greg Walden (R-Ore.) said neither party can afford to take the House for granted. But they maintained that GOP prospects remain strong thanks to successful recruiting and the down-ballot effect of having President Obama on the ticket.

Sessions declined to offer a specific prediction about the balance in the House come November, but suggested Republicans were likely to pick up seats.

He also observed that redistricting in 2011 allowed Republicans to shore up vulnerable members, freeing up resources for other races. He said Republicans had hardened 14 GOP-held seats, including that of Rep. Sean DuffySean Patrick DuffyFox News contributor: Black people tell me conditions in border detention centers 'are better than some of the projects' Trump mocks 'elites' at campaign rally Rally crowd chants 'CNN sucks' after Trump rips media MORE (R-Wis.), whose district had leaned Democratic and now leans Republican.

"This means I have to spend less money on those seats and can spend more on offense," he said.

Democrats and the DCCC have taken issue with the notion that the GOP gained an advantage in redistricting, arguing in a memo in early May that the process had been a wash and that senior Republicans were left more vulnerable in an anti-incumbent environment by the GOP's decision to focus on shoring up its freshmen.

Although polls show female voters moving in Obama's direction — with Obama leading Romney by almost 20 points among women in many swing states — Sessions said Republicans are reclaiming the upper hand.

He said Republicans would turn the corner with women — possibly around Labor Day — as voters realized that their children and families are worse off under Obama than they would be under Republican policies.

"The president has now abandoned Medicare. We won that issue," said Sessions, arguing that Republicans had won special elections due to a backlash from a $500 billion cut to Medicare that was included in Obama's healthcare reform law.

Sessions, who has led the campaign arm of House Republicans since 2008, said if a leadership election were held today, he believed he would be reelected as NRCC chairman. But he said he wasn't sure where things would stand after Election Day, and pointed to Walden as his likeliest replacement.

"One could not have had a more competent, professional person by their side," he said.

- This post was updated at 12:33 p.m.