Even Reynolds acknowledged the difficult environment. "I wish the president's numbers were 10 points higher," he said, adding that the bleak political environment has forced some of his more endangered incumbents, like Christopher Shays of Connecticut, to begin campaigning earlier.

And Reynolds' concern was evident last week at a notably downbeat news briefing, where he spoke about the vigor of Democratic challenges in three districts Republicans once considered unassailable — in Illinois, Ohio and in his own district in upstate New York.

"Chabot in Cincinnati will have a little more of a challenge than he usually has," he said, referring to Steve Chabot of Ohio.

In the Senate, Democrats need to pick up six seats, and view seven states as in play, giving them slightly less maneuvering room than they have in the house.

The shifts come as a series of polls bring ominous news for the party in power, going beyond a highly unfavorable view of Bush and congressional Republicans, and concern about the direction the country is heading.

Of particular concern for Republicans is that many of the party's most loyal supporters — who are crucial to the outcome in midterm elections, when turnout is typically low — seem discouraged and prone to saying home, according to several recent polls. At the same time, Democratic voters are described by officials in both parties as being the most energized they have been in recent memory.

Kohut of the Pew Research Center said that 29 percent of Americans in his most recent poll said they would vote against their own member of Congress. That is the highest percentage since 1994, when Republicans swept Democrats out of power. The finding, Kohut suggested, should give pause to Republicans who argue that while most Americans have an unfavorable view of Congress, they approve the performance of their own member of Congress.

In addition, Kohut said, 41 percent of Americans now say this Congress has achieved less than usual, and 34 percent say they view their congressional ballots this year as an opportunity to vote against Bush. Both figures are record highs.

Stuart Rothenberg, an independent analyst who tracks congressional races, said his latest forecast, to be distributed in the coming week, predicted that Democrats could make gains of eight seats to 12 seats. That is an increase from a prediction last month that Democrats would gain seven to 10 seats.

"When we say Democrats are positioned to gain eight to 12 seats, that certainly means the House is in play," Rothenberg said. "And those numbers are likely to go up. They are more likely to go up than they are to go down, that's for sure."