When the new Congress cranks up in January, there will be more women, many new faces and 11 fewer tea party-backed House Republicans from the class of 2010 who sought a second term.
Overriding those changes, though, is a thinning of centrist veterans in both parties. Among those leaving are some of the Senate's most pragmatic lawmakers, nearly half the House's centrist Blue Dog Democrats and several moderate House Republicans.
"This movement away from the center, at a time when issues have to be resolved from the middle, makes it much more difficult to find solutions to major problems," said William Hoagland, senior vice president of the Bipartisan Policy Center, a private group advocating compromise.
In the Senate, moderate Scott P. Brown, Massachusetts Republican, lost to Democrat Elizabeth Warren, who will be one of the most liberal members. Another GOP moderate, Richard G. Lugar of Indiana, fell in the primary election. Two others, Kay Bailey Hutchison of Texas and Olympia J. Snowe of Maine, are retiring.
Moderate Democratic senators such as Kent Conrad of North Dakota, Herb Kohl of Wisconsin, Ben Nelson of Nebraska, James Webb of Virginia are leaving, as is Democrat-leaning independent Joe Lieberman of Connecticut.
While about half the incoming 12 Senate freshmen of both parties are moderates, new arrivals include tea party Republican Ted Cruz of Texas and conservative Deb Fischer of Nebraska, and liberals Tammy Baldwin of Wisconsin and Hawaii's Mazie Hirono.
There's a similar pattern in the House, where 10 of the 24 Blue Dogs Democrats lost, are retiring or, in the case of Rep. Joe Donnelly, Indiana Democrat, are moving to the Senate. That will further slash a centrist group that just a few years ago had more than 50 members, though some new freshmen might join.
Among Republicans, moderates such as Reps. Judy Biggert of Illinois and New Hampshire's Charles F. Bass were defeated while others such as Reps. Jerry Lewis of California and Steven C. LaTourette of Ohio decided to retire.
"Congress seems to be going in the opposite direction of the country, just as the country is screaming for solutions to gridlock," said Democratic strategist Phil Singer.
Whether the changes are good is often in the eye of the beholder.
Seventy-one of the 83 House GOP freshmen of 2010 were re-elected Nov. 6, but 11 lost, including one of the group's highest profile members, conservative Rep. Allen B. West, Florida Republican. Another faces a runoff in December.
"Some of the people who are the anti-government ideologues, some of them are gone," said House Minority Leader Nancy Pelosi, California Democrat. "And that message has been rejected by the American people."
Sal Russo, strategist for the Tea Party Express, said such departures would be balanced by newly elected conservatives, including the Senate's Mr. Cruz and GOP Reps.-elect Ted Yoho of Florida and Mark Meadows of North Carolina.
"Pretty much everybody that ran in 2012 was talking about the economic woes we face, stopping excessive spending, controlling unsustainable debt," he said.
Overall, the new House is on track for a 234-201 Republican majority, a narrowing of their 242-193 advantage today, which includes five vacancies. Democrats will control the Senate 55-45, up from 53-47.
A dozen of the 100 senators and at least 81 of the 435 House members, almost one-fifth, will be in their first term, slightly above historic averages. The Associated Press hasn't declared winners in two House races.
Many newcomers, in Washington for orientation sessions after their election, described a need to compromise. Some also made it clear there will be plenty of fuel for partisan clashes.
"I'm going in open-minded," said conservative Rep.-elect Roger Williams, Texas Republican. "But I have certain core values like we all do, and I'm not going to waver on that."