Two of them are senior members of the House Judiciary Committee who played key roles in civil rights legislation and the Nixon impeachment proceedings. Another has been a major force on issues from the Panama Canal treaties to civil service reform. A fourth is praised by an opposition-party colleague as a "conscientious, effective" member of the powerful Appropriations Committee.

But after next Tuesday at least two, and maybe more, will be officially lame ducks, the first of a long list of victims of what promises to be a turbulent political year.

Because of redistricting on new census numbers, most members of the House are running in more or less unfamiliar territory, creating new vulnerabilities. Redistricting brings some members their first serious challenges in many years. Others find themselves thrown in against old friends, or pushed into premature retirement.

The candidates in Tuesday's Illinois primary, the first in the nation, suffer all those afflictions. Individual careers are obviously affected, but so is the House, a body so large that it is dependent on relatively few people to get its work done.

The Illinois primary shows how capricious politics can be in a year like this one, not just with individuals but with the institution of which they are a part.

The reality of Illinois is that the House is going to lose some people who will really be missed, and get back some others whose contributions are almost invisible to their colleagues.

Here are sketches of a few of those people.

When George M. O'Brien (R-Ill.) ran for Congress in 1972, his biggest help came from the Republican incumbent in the neighboring district, Edward J. Derwinski. In Washington, Derwinski and O'Brien often commute to work together. But now, thanks to a federal court decision choosing the Democrats' Illinois redistricting plan, they are going up against each other in a south suburban district in which only one can survive.

All this explains why O'Brien refers to their Republican primary as "this ordeal . . . the toughest race of my life." With prodding from Derwinski, the No. 2 man on the House Foreign Affairs Committee, the White House dangled a number of ambassadorships before O'Brien, 64, hoping to avoid an intra-party bloodletting. But O'Brien did not take the bait.

A similar situation in suburbia north of Chicago was resolved when 20-year veteran Rep. Robert McClory (R) decided to retire rather than contest the younger Rep. John E. Porter (R), who was redistricted into his territory.

A quiet, courtly man, McClory, as ranking Republican on the Judiciary Committee, has shown an unusual degree of independence, taking positions on open housing, gun control, the Equal Rights Amendment and the Nixon impeachment that angered some conservatives in his wealthy, conservative area.

O'Brien and Derwinski are two other members who rank high in their colleagues' estimation. O'Brien, a Yale Law School graduate, did not come to the House until he was in his mid-50s.

But Rep. Neal Smith (D-Iowa), chairman of the Appropriations subcommittee on which O'Brien is the ranking Republican, expressed the consensus when he said O'Brien is exactly the sort of conscientious member on whom the detail work of Appropriations depends.

"Even under the partisan conditions of last year," he said, "we were able to get together and work things out. He doesn't relish confrontation; he'd rather be effective."

As for Derwinski, he is, at 55, at once one of the recognizable "characters" in the House and one of its most effective legislators. He is a big, bulky man with a bristling crew-cut and an irrepressible sense of humor.

When he debates, as he often does, colleagues listen for laughs, but absorb his message. On foreign policy he has moved far from the isolationist stance he took in his first election campaign in 1958, and has become a skillful advocate of foreign aid and the implementation of the Panama Canal treaties.

As ranking Republican on the Post Office and Civil Service Committee, Derwinski was vital to the passage of President Carter's civil service revisions. A Democrat who went through that fight with him calls him "a fine, realistic legislator. He took a lot of guff from the Young Turk Republicans for that fight, but he knew it had to be improved and he chose to be constructive. I'm a great admirer of his."

As redrawn, the district has four times as much of O'Brien's old territory as Derwinski's. But in this contest, as in the House, Derwinski has proved to be the more aggressive of the two.

He captured the endorsement of the strong Bloom Township GOP organization, even though that area moved out of his district into O'Brien's 10 years ago. And Der- winski went into the final three weeks of the campaign with $61,000 in unexpended campaign funds, six times as much as O'Brien reported.

Their race is regarded as a tossup, but many in the House feel that, whomever is eliminated, the House loses.

For 16 years Rep. Tom Railsback (R-Ill.) enjoyed the good life as a member of Congress. He came to the House as a 34-year-old lawyer, gained a place on the Judiciary Committee and scores of friends in the House gym.

He took what might have been a marginal district--a mixture of rural Republican counties and a labor stronghold in Moline-Rock Island--and built a secure political base by salting his GOP voting record with support for civil rights and some labor positions.

In 1974, while the nation watched, he put together the small bloc of middle-of-the-road Republicans which ultimately swung the verdict against Richard M. Nixon.

Railsback became even more of a maverick in Republican eyes when he joined liberal Democrats in sponsorship of legal services for the poor and curbs on political action committees. But he faced no serious political problems until this past year.

Last March he got unwanted front-page publicity as one of the three House members who shared a Florida vacation cottage with lobbyist Paula Parkinson, the focus of a Playboy camera. Now, the problems have grown to the point that Railsback is in what may be an uphill fight for survival in Tuesday's primary.

The redistricting plan hurt him, stripping him of three counties where he has run well and adding six new farm counties. It also brought him his first primary challenger, and a formidable one, 39-year-old state Sen. Kenneth G. McMillan, an able, aggressive legislator who represented much of the new territory in Springfield.

McMillan has the strong rural base that Railsback lacks. A farmer, he worked for former secretary of agriculture Earl L. Butz and for the Illinois Farm Bureau, whose official neutrality does not inhibit strong pro-McMillan efforts by its officers.

McMillan also has drawn backing from anti-abortion and national conservative groups, delighted to have a chance to discipline the independent Railsback.

"It is," Railsback acknowledges, "a classic confrontation between a moderate and a very strong conservative." With the endorsement of a widely diverse group of colleagues, from liberal Rep. Jim Leach (R-Iowa) to conservative Rep. Jack Kemp (R-N.Y.), and the help of Minority Leader Robert H. Michel (R-Ill.), part of whose territory he absorbs, Railsback is trying to portray his role in Congress as a useful bridge between the wings of the GOP and between the two parties.

That is how he is seen by those with whom he serves. Rep. Robert W. Kastenmeier (D-Wis.), a liberal on the Judiciary Committee, says that "As a moderate, he plays a very constructive role. His views and mine are rarely the same, but on so many issues we've been able to reach agreements that would have been impossible with someone else."

Railsback argues that only a moderate can win in November; that if McMillan is nominated, "organized labor will blitz him" in the fall. But he has been kept on the defensive, rebutting charges that his attendance record and his support for President Reagan are below par.

With McMillan's rural base, Railsback depends on support in Galesburg, which he last represented 10 years ago, Peoria County, where he is a newcomer to Michel's territory, and Rock Island County, where the GOP primary vote traditionally is very low.

There was a time when the phrase "the Chicago delegation" meant something special in the House: a bloc of votes, in lockstep obedience to Democratic Mayor Richard J. Daley.

But no longer. Two Chicago congressmen are facing serious renomination fights. Politically, they are complete opposites. Legislatively, neither would be missed by most of their colleagues. But whether their replacements would be improvements is another question.

Daley made John G. Fary (D) a congressman, as Fary is proud to tell you. The tavern owner had served for 20 years in the Illinois Legislature, where his most notable accomplishment was the "bingo bill," legalizing that form of gambling for churches, veterans' and charitable groups. In 1975 Daley called in Fary, then 64, to discuss a successor to Rep. John Kluczynski (D), who had died in office at 78.

As Fary recalls the moment, the mayor said, "I have a young man in mind who's been clean, decent and respectable, who's never done anything to disgrace himself, his family or the party."

"I'm with you, mayor," Fary recalls saying. "Who's the candidate?"

"It's you," the mayor replied, and Fary adds: "I just about collapsed, I was so shook."

Fary came to Congress, joined the Public Works and Transportation Committee, and disappeared from public view. A Republican who serves with him says, "He is a loyal and sincere message carrier for whatever is left of the Chicago organization. He is reasonably effective on Chicago matters, and beyond that he is not inclined to attempt to change the nation."

A Democrat on his committee says, "Fary attends every meeting conscientiously. He's no bolt of lightning, but he's always there. The staff gives him questions to ask, and he asks every one of them."

Fary is under challenge Tuesday because the late mayor's son, Cook County State's Attorney Richard M. Daley, has an ally he wants to advance, Alderman William O. Lip- inski (D).

Lipinski, 43, promises more aggressive service. He says Fary promised two years ago this would be his last term, and should have withdrawn when the party endorsed Lipinski for the seat this year. He says Mayor Jane Byrne (D) is supporting Fary only because of her constant feud with young Daley. And he says Fary also is being manipulated "by a couple folks on his payroll who don't want to lose their high-paying jobs."

Lipinski speaks with authority on jobs. His contributors' list is studded with the names of employes of the city of Chicago and the Park District, where Lipinski once worked.

The alderman was only slightly embarrassed when The Chicago Tribune revealed that his political organization had made a $1,200 contribution to the Republican secretary of state to protect eight Lipinski patronage jobs in that office, one of them held by the alderman's mother.

"People tell me," Lipinski says, "that my only mistake was that I did it openly and honestly reported it. But being an honest man, and somewhat naive, I did it that way."

Nearby--but a world away, in the racially polarized city--freshman Rep. Gus Savage (D), 56, is facing a challenge from the mayor's candidate, former Chicago Transit Authority chairman Eugene M. Barnes (D), state Rep. Monica Stewart (D) and her former campaign manager, Bruce Crosby (D).

Savage beat the organization-endorsed candidate in the 1980 primary and became the city's third black congressman. His only publicity came when he attacked the Washington, D.C., police department as racist for arresting his son on the charge of driving an unlicensed car.

Savage, like Fary, is on Public Works, but his reputation is different from his neighboring congressman's. "He is noted more for his absence than his presence," said a Democratic colleague who requested anonymity. "I went to a meeting with people from his district and it was embarrassing. He didn't have the information on what they were talking about, and I had to bail him out." Another Democrat on the committee said, "Gus? You never see him around here."

Savage's absenteeism--the worst in the Illinois delegation, according to Congressional Quarterly's analysis of 1981 roll-call votes, which gave him a 50 percent score--was made an issue by an article in The Chicago Sun-Times. Savage said the criticism was the work of "the white press" and "phony liberals," and said "Reagan and racism are the real issues."

"I'm not going to let white folks tell me what to do," he said. "I'm not going to sit like a bump on the log and vote on every procedural point."

Rep. Parren J. Mitchell (D-Md.) came to Chicago to support Savage, saying, "If the power structure here got Gus Savage, the boys around the country would say, 'We got Gus.' Next it would be Harold Ford, then Lou Stokes, then Parren."

Barnes is considered the strongest threat to Savage, but with a divided field few are willing to bet if anyone will end his congressional career.