WASHINGTON -- When the next 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 pragmatic, 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.

That could leave the parties more polarized even as President Barack Obama and congressional leaders talk up the cooperation needed to tackle complex, vexing problems such as curbing deficits, revamping tax laws and culling savings from Medicare and other costly, popular programs.

"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 Brown, R-Mass., lost to Democrat Elizabeth Warren, who will be one of the most liberal members. Another GOP moderate, Richard Lugar of Indiana, fell in the primary election. Two others, Kay Bailey Hutchison of Texas and Olympia Snowe of Maine, are retiring.

Moderate Democratic senators such as Kent Conrad of North Dakota, Herb Kohl of Wisconsin, Ben Nelson of Nebraska, Jim Webb of Virginia are leaving, as is Democratic-leaning independent Joe Lieberman.

While about half the incoming 12 Senate freshmen of both parties are moderates, new arrivals include tea party Republican Ted Cruz of Texas, conservative Deb Fischer of Nebraska, and liberals such as Tammy Baldwin of Wisconsin and Hawaii's Mazie Hirono.

There's a similar pattern in the House, where 10 of the 24 Democratic Blue Dogs lost, are retiring or, in the case of Rep. Joe Donnelly, D-Ind., 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 like Reps. Judy Biggert of Illinois and New Hampshire's Charles Bass were defeated while others such as Reps. Jerry Lewis of California and Steven 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.

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.

For the first time, more than half of House Democrats -- 105, in this case -- will not be white males.

One white male will be Rep.-elect Joseph Kennedy III, a Massachusetts Democrat whose father was Rep. Joe Kennedy, D-Mass., and grandfather was New York Sen. and Democratic presidential candidate Robert Kennedy. When the newest Kennedy takes office, it will end the only two years since 1947 without a member of his family in Congress.