WASHINGTON — House Democrats are stepping on the gas, with plans to target over 100 Republican-held congressional districts in the November midterm elections.

At House Democrats' annual conference on Thursday, Rep. Ben Ray Lujan of New Mexico, the chairman of the Democratic Congressional Campaign Committee (DCCC), is expected to tell colleagues the committee is expanding the battleground to include 101 Republicans — the largest in a decade, a Democratic source familiar with the matter told NBC News.

The seven new targets push Democrats even deeper into Republican territory in South Carolina, Wisconsin and Texas. And they include the Ohio seat held by the man charged with defending the GOP's majority, Rep. Steve Stivers, chairman of the National Republican Congressional Committee. (Republicans are also targeting Lujan.)

The DCCC's own polling of key districts has been more promising than national trends, showing President Donald Trump underwater not just in the 23 GOP-held districts Hillary Clinton won, but also in the more than 60 districts Trump won, and the 11 where retirements have left the seat open.

Democrats are now fielding candidates in all but 12 of the 238 districts held by Republicans, according to Lujan, including in places like Alabama, where Democrats are competing in every single district for the first time in years. The idea is to expand the map as much as possible and hope to ride the potential wave.

"They should do some re-evaluating," Lujan said of Republicans.

Other new DCCC targets include South Carolina’s 5th Congressional District, where Democrat Archie Parnell outperformed expectations in a special election last year and is running again; New Jersey’s 4th Congressional District, represented by veteran GOP Rep. Chris Smith; Wisconsin’s 7th Congressional District, held by Rep. Sean Duffy; and Maryland’s 1st Congressional District, which includes the state’s conservative Eastern Shore, where Democrats initially planned to have their retreat.

The Democrats' move comes as recent polls have revived Republicans' hopes of retaining their majority, even as they acknowledge Democratic advantages.

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Trump's approval rating has ticked up, while Democrats' lead in the generic ballot test, a key measure for congressional races, has dropped from 13 points in December to around 6 points, according to the Real Clear Politics polling averages.

"It seems like Republicans are rallying to their president and party a little bit in recent weeks, leading to an improvement for the president's standing and the GOP standing in the House generic ballot," said Kyle Kondik, an analyst at the University of Virginia’s Center for Politics.

Meanwhile, the economy remains strong and Republicans' multimillion dollar efforts to sell their tax cut plan and tie it to economic gains appears to have paid some dividends.

"I just looked at some numbers. You've even done better than you thought, I think," Trump told GOP lawmakers at their retreat last week.

The open question is whether that data represents the beginning of a correction for Democrats after months of nothing but positive data, or a relatively insignificant blip on the party's way to winning the 24 seats they need to flip the House.

Former Vice President Joseph Biden speaks to House Democrats during their 2018 Issues Conference on Capitol Hill on February 7, 2018 in Washington. Mark Wilson / Getty Images

Former Vice President Joe Biden made no effort to temper his optimism Wednesday while addressing House Democrats on the first day of their conference, which had been moved from a resort on Maryland's Eastern Shore to the U.S. Capitol because of the ongoing government funding crisis.

"Go out and holler guys, go out and holler, you are going to win back the House!" Biden told Democrats. "Others who have been around as long as I have, sometimes you just feel it, you can taste it, there is something out there if we don’t miss this opportunity — we have a great opportunity."

Biden is one of the few national Democrats who can be helpful to candidates almost anywhere in the country, and he pledged to do so. "I will spend all the time any one of you want me to making sure we win back the house," Biden said.

As he spoke, House Minority Leader Nancy Pelosi, D-Calif., was about two-thirds of the way through her record-breaking marathon speech on the House floor.

The speech was about defending Dreamers, but by speaking on her feet for eight hours, the 77-year-old Pelosi also sent a message to the world, and her own caucus, that she’s not going anywhere.

Many see Pelosi as a liability for her party, and Republicans plan to once again build their midterms playbook around her, arguing she is more politically toxic than Trump. Two new ads from two GOP groups use Pelosi to attack the Democratic candidate in a Pennsylvania special election next month — even though the candidate had said Pelosi should step aside.

One thing Democrats no longer have is the element of surprise.

House Republicans are determined to not be caught sleeping, with party leaders urging their members to prepare for the fight of their lives, even if they haven't had a strong challenger in years.

In his own presentation to lawmakers at the GOP retreat last week, Stivers delivered three main points, according to a source in the room: 1) Be ready, 2) Sell tax reform and 3) Run a real campaign.

Despite the recent downturn in some polling, Democratic lawmakers remained bullish on Wednesday. Some privately expressed concern about overconfidence, given their experience with Hillary Clinton in the 2016 presidential campaign.

"I don’t take anything for granted, but I do know momentum when I see it," Lujan, the DCCC Chair, said in an interview with NBC News. "History is on our side, the data is on our side."