WASHINGTON – Before Congress recessed earlier this month, Democratic leaders insisted House Republicans were in for a November surprise, but the GOP is confident that Democrats’ bid to retake the House will be foiled by the power of incumbency and a controversial redistricting in Texas engineered by Majority Leader Tom DeLay.

With just over a week to go before voters cast their ballots, the Republicans’ 12-seat majority in the House appears solid, although the Democrats may be able to whittle down the margin with wins in Pennsylvania. However, with only 30 or so seats across the country considered competitive and a dozen thought to be toss-ups, even reducing the GOP majority is going to be a tough job for the Democrats, Republicans and political analysts say.

Stuart Rothenberg, who publishes a well-respected political report that tracks congressional races, said Republicans are not terribly vulnerable going into Election Day. “It is difficult to imagine substantial Democratic gains,” he said. In the past three congressional elections, 98% of incumbents were returned to office, and analysts don’t expect this election to be much different.

Texas and Pennsylvania are at the center of the fight over control for the House. Because of Mr. DeLay, who was the architect of redistricting in Texas, the scrapping in the Lone Star State has been weighted in the GOP’s favor. Last year’s redistricting, which prompted Democratic state lawmakers to leave Texas in an unsuccessful bid to deny a quorum for approval, resulted in Republican-majority voter registration in five potentially competitive seats. It also led one Democrat to retire and another to switch parties.

If the Texas ploy pays off and the Democrats make no gains elsewhere, the GOP could boost its House majority. And if Democrats do manage to cap ture Republican seats outside of Texas, such as in Pennsylvania, the redistricting is likely to act as a firewall protecting the GOP majority, said a Republican strategist, Grover Norquist. “We are doing well in the House races,” Mr. Norquist told The New York Sun. “In Texas, the Democrats will be fortunate to win one of the five competitive contests in the state.”

The chairman of the National Republican Congressional Committee, Rep. Thomas M. Reynolds of New York, says he also expects the redistricting to pay off. The White House has been helping, with President Bush appearing in photo-ops for the Texas GOP candidates and Vice President Cheney lending his weight to their fund-raising efforts.

Texas’s Democratic incumbents – Reps. Charles Stenholm, Nick Lampson, Max Sandlin, Chet Edwards, and Martin Frost – have mounted vigorous fights to upset the GOP plan, but all four are finding it hard going, and the chairman of the Democratic Congressional Campaign Committee, Rep. Robert Matsui of California, admitted earlier this month that only a couple of them might prevail.

Of the five, Mr. Edwards probably stands the best chance of reelection. The 17th District was redrawn to favor his GOP challenger, Arlene Wohlgemuth, a state legislator, but Mr. Edwards is a strong campaigner and the district includes Texas A&M, which the Democrat attended. Last week, a Capitol Hill newspaper, Roll Call, took Mr. Edwards off its list of vulnerable incumbents.

In the state’s 32nd District, centered in the Dallas suburbs, Rep. Martin Frost, the only Jewish member of the Texas House delegation, is banking on Jewish and Hispanic votes to defeat Rep. Pete Sessions. However, he lags the Republican in recent opinion polls by about 6%, despite running a highly aggressive campaign that has occasionally wrong-footed Mr. Sessions. The race for Texas’s 32nd District is likely to be the most expensive House contest in the country, with both men spending $4 million each.

The veteran congressman Charles Stenholm has the hardest of all fights on his hands in his member-vs.-member contest with Rep. Randy Neugebauer, who has enjoyed a consistent lead in recent opinion polls. The race in District 19 in west Texas is breaking along party lines, which favors Mr. Neugebauer hugely. Four years ago, Mr. Bush got 73% of the vote in the district and Mr. Neugebauer has been linking his Democratic opponent at every turn with Senator Kerry. Because of the redistricting, two thirds of the voters are new to Mr. Stenholm, a 26-year-veteran congressman who has normally been a shoo-in.

In response, Mr. Stenholm has sought to link the Republican with the House majority leader, saying Mr. Neugebauer “votes 98% of the time with Tom DeLay.”

Like other Texas Democrats, Mr. Stenholm has made much of the House Ethics Committee’s recent series of rebukes of Mr. DeLay, one of which was directly tied to the majority leader’s pressure on Texas legislators to redraw the state’s congressional district lines. The “integrity and corruption” attacks on Mr. Delay, Texas’s most powerful congressman, have so far proven ineffective, along with similar Democratic attacks on the House majority leaders in states such as Pennsylvania, where two or three districts are highly competitive and where the Democrats hope to capture the seat of Rep. James Greenwood, a moderate Republican who is retiring this year.

“I think Eastern Pennsylvania, after Texas, is the biggest battleground in the entire country,” said a spokesman for the Democratic Congressional Campaign Committee, Greg Speed. In all, three districts in Pennsylvania are competitive.

Nationally, more Republican incumbents than Democrats are stepping down, fueling Democratic hopes. In Washington State, Democrats have set their sights on gaining the open seat of Republican Rep. George Nethercutt, who is running for the Senate. Retiring Republicans have also created opportunities for a change of seats in New York, Louisiana, and Colorado. Democratic retirements have created two opportunities for Republican gains in Louisiana and Kentucky.

A few incumbents also face tough reelection fights, including Connecticut’s moderate Republican Rep. Christopher Shays, who Democrats believe is highly vulnerable to a challenge from Westport First Selectman Diane Farrell. She has raised more than $1 million with the assistance of Senator Clinton and other prominent Democrats who are targeting the race, and she is trying to use discontent with the Iraq war against the incumbent. Mr. Shays has turned to Senator McCain, who has stumped for him.

The Iraq War and the war on terror resonate in the district, where many soccer moms have become security moms. Dozens of Connecticut residents were killed in the Al Qaeda terror attack on New York.

Mr. Shays strongly supports the president on Iraq and was the first U.S. congressman to visit the country after the invasion. Through hearings in the House, he has secured a national reputation on terrorism and homeland security. In the first debate with Ms. Farrell, he said: “I am intimately involved in this issue, I eat, sleep, I dream about these issues every day.” Ms. Farrell argues the president misled the country with false justifications for the war.