WASHINGTON — WASHINGTON -- The new Republican Congress is dominated by conservative activists who, after years on the back benches, now have the power to set their own populist agenda of tax cuts and anti-government measures and to tell President Clinton: Take it or leave it.

The transformation will be most pronounced in the House, where Newt Gingrich, the pugnacious rebel who engineered much of yesterday's Republican sweep, will call the shots from the speaker's rostrum. Until yesterday, that precious perch belonged to Democrat Thomas S. Foley, who appeared in grave danger last night of losing not only his majority but his own seat. He would be first House speaker since 1860 to be turned out by the voters.


In a body where the minority party has traditionally been treated as interlopers, the speaker's post gives Mr. Gingrich and the Republicans enormous authority over committees, staff, rules and the levers of power that the Democrats have held so jealously for four decades.

"The entire character of the House of Representatives will be different," predicted Nicholas E. Calio, who was chief White House lobbyist for President George Bush. Among the missing will be the larger-than-life presence of Dan Rostenkowski, the Chicago Democrat and Ways and Means Committee chairman who was perhaps the most powerful man in Congress until his indictment earlier this year on corruption charges.


With its new Republican majority, the Senate has also been infused with conservative firebrands, several of whom got their training under Mr. Gingrich in the House by lobbing grenades at Democratic social programs and tormenting Democratic leaders with demands for ethics investigations.

They include Arizona's John Kyl, a past chairman of the House Conservative Opportunity Society who helped force disclosure of rubber-check writers in the House banking scandal, and Rep. James M. Inhofe of Oklahoma, who once asserted that Congress was home to "a bunch" of Communists and who credits his election to "God, guns and gays." Former Rep. Michael DeWine of Ohio defended President Ronald Reagan so vociferously during the Iran-contra hearings that he earned the nickname "DeWhine."

Many of the new senators are not only more conservative than those they replaced; they also lean harder to the right than did those who arrived with the last Republican wave, the one that elected Mr. Reagan in 1980.

"This is by far the most conservative [freshman] class in history," said Gary L. Bauer, a former Reagan official who now promotes conservative social issues. "There are more Reagan Republicans than when Reagan was president."

At the same time, the Democrats who survived yesterday's onslaught -- such as Sens. Paul S. Sarbanes of Maryland and Edward M. Kennedy of Massachusetts -- tend to be among the most liberal.

So, as the newly elected Republican activists join such conservative stalwarts as Jesse Helms of North Carolina, Phil Gramm of Texas and Strom Thurmond of South Carolina, they will gaze across the Senate chamber at a Democratic contingent ever more firmly rooted on the left: Mr. Kennedy, Jay Rockefeller of West Virginia, Thomas A. Daschle of South Dakota, the likely new Senate minority leader.

The contrast on the Senate Banking Committee -- where Mr. Sarbanes has lost his first chance at a major chairmanship in 18 years to New York Republican Alphonse M. D'Amato -- will be particularly ironic. The Marylander now becomes the top Democrat in charge of watching Mr. D'Amato, a strident critic of President Clinton's handling of the Whitewater matter, conduct his own Whitewater investigation -- complete with subpoena power.

This polarization makes it likely that attempts by Mr. Clinton and the Republican leaders to find common cause on a few key initiatives, such as welfare reform, will break down into the sort of partisan strife that poisoned the close of the 103rd Congress. In the next Congress, though, the Democrats will probably do the filibustering, and Mr. Clinton might be forced for the first time to take the cap off his veto pen.


"If you liked the 103rd Congress, you'll love the 104th," quipped Sen. John B. Breaux, a Louisiana Democrat.

Senate Republican leader Bob Dole of Kansas has promised that the first order of business in the new Congress will be consideration of a balanced budget amendment, which Mr. Clinton and the Democratic leaders killed last year. Mr. Gingrich has a similar proposal in the legislative package he has promised to put to a vote in the first 100 days of Congress, called "Contract for America."

Senator Dole, however, may have trouble controlling his own forces without a Republican president to help enforce the discipline, predicted Kenneth Duberstein, a former White House lobbyist for Mr. Reagan who worked with Mr. Dole the last time he was Senate majority leader, in the 1980s. Senators Dole and Gramm are both prospective challengers to Mr. Clinton in 1996, which makes their competition a factor in all party calculations.

Today's reality is that neither party can truly claim control of Congress unless it has the 60 votes needed to overcome a Senate filibuster, said James Thurber, director of the Center for Congressional and President Studies at the American University.