WASHINGTON – Republican gains in the House and Senate could spell trouble for the Northeast, where moderate GOP lawmakers often align themselves with Democrats on social, environmental and transportation issues.

What may further aggravate the situation is the resentment some GOP moderates – particularly in Connecticut – feel toward Democrats who aggressively worked against them in the election campaigns.

And in at least one case, the moderates may lose one of their own to the other side. Sen. Lincoln Chafee, R-R.I., is considering casting off his GOP robes to become a Democrat.

“Things are going to be much harder, given the numbers,” said Sen. Christopher Dodd, D-Conn. “I think we’re going to find ourselves in serious trouble.”

Republicans gained four seats in the Senate, and will hold a 55-44 majority, with one independent – Sen. Jim Jeffords of Vermont – who generally sides with Democrats. In the House, Republicans will hold a 231-200 edge, with three races still undecided.

Moderate Republicans such as Chafee and Sens. Olympia Snowe and Susan Collins of Maine often have banded together with Democrats in the Senate on issues of particular importance to New England. And they have provided critical votes to block a variety of GOP initiatives, including drilling for oil in Alaska’s Arctic Refuge, the Bush energy bill and air pollution issues.

Northeastern lawmakers have battled against efforts by the Bush administration to change clear air standards and supported legal challenges over polluted air that drifts eastward from fossil fuel-burning plants in the Midwest.

Frank Maisano, an energy industry lobbyist for Bracewell & Patterson in Washington, said the GOP gains won’t help much on regional issues.

“The New Hampshire guys are still going to vote with [New York Democratic Sen.] Chuck Schumer,” he said. “The regional differences are still big, and we will have to try to find some common ground.”

In the highway funding bill that is being negotiated by the House and Senate, some Northeast states are struggling to beef up their allotments. But with less pull in the Senate to argue against changing the formulas that now may be more difficult.

The other impact could be on the intelligence reform bill, where Sen. Joe Lieberman of Connecticut and Collins have worked together to push for an overhaul of the intelligence community. The election has fueled Republican efforts to stall the bill at least for now.

Still, some moderates say they may have a larger role to play in the House.

“Democrats need moderate Republicans to hold the line and that’s how the deals are cut,” said Rep. Rob Simmons, R-Conn.

Some fences need to be mended first. Simmons and Rep. Christopher Shays, R-Conn. – the only two House Republicans in southern New England – came under aggressive attacks by Democrats, including House Minority Leader Nancy Pelosi, D-Calif., who campaigned for their opponents.

“I’m eager to have a conversation with a few of my colleagues,” said Shays. “They went over the line.”

He pointed to Rep. Rosa DeLauro, D-Conn., and Rep. John Lewis, D-Ga., who railed against him on behalf of his Democratic challenger, Diane Farrell.

“It was difficult to see John Lewis come in. He’s a good friend,” Shays said. “You don’t choose to go after the very people we need to work with.”

DeLauro said the Democrats simply criticized the Republicans’ records, but added that lawmakers will continue to reach out to GOP moderates.

“These were hard-fought battles because it was for control of the House,” she said. “A person’s record is fair game.”