U.S. Rep. Roscoe Bartlett is fighting an uphill battle this election season after redistricting cut Republican constituents out of his district. (Melina Mara/THE WASHINGTON POST)

For the first time since he was elected two decades ago, Rep. Roscoe G. Bartlett is in real danger of losing his seat.

The Maryland Republican survived an April primary against seven opponents, receiving just 44 percent of the vote. Now he must introduce himself to hundreds of thousands of new voters in a district that was redrawn by Democrats specifically to oust him. Never a strong fundraiser, Bartlett faces a deep-pocketed challenger, financier John Delaney (D), and there is no sign that national Republicans plan to bail him out.

In the lull of summer, both candidates are focused on the basics of campaigning — knocking on doors and raising cash — ahead of an inevitably intense fall battle in which Bartlett looks like the underdog.

The nonpartisan Cook Political Report and Rothenberg Political Report both rate Bartlett and Rep. Joe Walsh (Ill.) as the two most endangered Republican incumbents in the country. A Delaney campaign poll released after the primaries showed him leading Bartlett by nine points.

“I think things would have to go pretty far south nationally for Democrats for Bartlett to have a chance,” said David Wasserman, the Cook Report’s House editor.

Yet Bartlett remains optimistic that voters will send him back to Congress for an 11th term.

“It’s a competitive race,” Bartlett said last Monday in Frederick, where he hosted his annual Go Green Energy Conference at the county fairgrounds.

When they drew the new congressional map last year, Democratic leaders in Annapolis chopped off the Republican-leaning eastern portion of Bartlett’s district, while adding a slice of more liberal Montgomery County, where voters have never seen Bartlett’s name on the ballot.

“We’re working hard to get acquainted there, and I think that people are learning who we are, and we feel pretty positive about it,” Bartlett said.

Bartlett’s outreach includes emphasizing views — such as his longtime support for renewable energy, highlighted at last week’s conference — that might be appealing to moderates. “Many of my fellow Republicans, they haven’t had time to properly focus on this,” Bartlett said of the need to find alternative energy sources.

But Democrats think Bartlett’s 20-year voting record, in which has been solidly conservative on most issues, will undermine any such effort. He has a lifetime legislative rating of 93 percent from the American Conservative Union.

At 86, Bartlett is the second-oldest member of the House. A Seventh-day Adventist with 10 children, he is a scientist and former college professor who also raises goats on a sprawling farm in Buckeystown.

It’s difficult to assess where or how much Bartlett has been appearing in the district, because his campaign has repeatedly declined to provide any information about his schedule or allow reporters to tag along. (The same was true during the Republican primary.)

Still, local Republicans said he has been a frequent presence on the trail.

“I’m seeing a lot of active campaigning [from Bartlett], more so in Montgomery County than Frederick County,” said Stephen Gottlieb, chairman of the Frederick County Republican Central Committee. But because of redistricting, Gottlieb is worried that many voters in the area don’t realize who will be on their ballots in November. “My concern is I don’t think enough people are engaged in this,” Gottlieb said.

Bartlett also has the challenge of courting the 56 percent of Republicans who cast their primary ballots for someone else. Those voters included Frederick Mayor Randy McClement (R), who supported state Sen. David R. Brinkley (Frederick) in that contest.

“I appreciate what the congressman has done for all these years, but I look at change as necessary,” McClement said Monday in explaining his initial choice. But once the primary was over, McClement felt it “was time to move on” and back Bartlett.

Delaney’s campaign, meanwhile, has spent the post-primary period holding dozens of volunteer events and making more than 100,000 calls to voters.

Unusual for a competitive race, the two campaigns have not directly engaged each other by trading volleys in the media.

“There hasn’t been the back and forth,” said Justin Schall, Delaney’s campaign manager. “It’s given us time to focus on infrastructure or messaging, really allowed to concentrate on building up our campaign operation.”

Delaney has also been soliciting public endorsements and appearances from people and groups who backed his primary foe, state Sen. Robert J. Garagiola (D-Montgomery).

Both candidates have also been busy fundraising.

Delaney, founder of the Chevy Chase commercial lender CapitalSource, raised far more than his opponent from outside donors in the Democratic primary while contributing more than $1.6 million of his own. From April through June, Delaney raised $452,000, and he had about $220,000 in the bank as of June 30. Bartlett did better than usual in the second quarter, raising $377,000, with $548,000 left.

In Virginia, millions of dollars from outside groups have poured into the state to buy TV ads, both for the heated Senate contest between George Allen (R) and Timothy M. Kaine (D), and for the presidential race. Nationwide, Republican and Democratic campaign committees have reserved airtime in dozens of key House districts.

Yet none of that outside money or attention has found its way into Maryland’s 6th District, and perhaps it never will. Washington is a prohibitively expensive market in which to buy broadcast airtime, and both sides know Delaney has the means to write a seven-figure check if he deems it necessary.

“The parties’ energies are focused elsewhere, in part because Republicans didn’t get the Democratic candidate they wanted in the primary,” Wasserman said. “It’s unclear whether Republicans can afford to bail Bartlett out.”