CARTER HAS WAGED a valiant struggle to switch Illinois to his column, but the final Chicago Sun-Times poll showed a 5-point Reagan surge had carried him narrowly in front. It was Reagan 45.1, Carter 44.2 and Anderson 10.7. GOP polls -- which showed Reagan leading even before the debate -- picked up the same improvement. Carter has a higher share of the Chicago vote than in 1976, but the performance of the Democratic organization may be hurt by the feud between Mayor Jane Byrne (D) and State Sen. Richard M. Daley (D), son of the late mayor and candidate for Cook County state's attorney. Because of Anderson, Reagan is getting a smaller margin out of the suburbs than Ford did in 1976, but he is running better downstate. Statistically, the race is close, but the momentum and edge are with Reagan.

Secretary of State Alan J. Dixon (D), 53, is running 23 points ahead of Lt. Gov. David C. O'Neal (R), 43, in the race to succeed retiring Sen. Adlai E. Stevenson (D) in a race where neither candidate has been mistaken for a scholar or a statesman.

The only seriously challenged House member is Rep. Paul Findley (R), whose friendliness toward the Palestine Liberation Organization has attracted big financial support to his challenger in this strongly Republican district, former state representative David L. Robinson (D). Other changes of faces but not parties include State Sen. Harold Washington (D) who defeated Rep. Bennett M. Stewart (D) in a primary; publisher Gus Savage (D) for retiring Rep. Morgan F. Murphy (D), and State Sen. Lynn M. Martin (R) over County Treasurer Douglas R. Aurand (D) for Anderson's old House seat. INDIANA (13)

INDIANA IS LOCKED UP for Reagan, and Lt. Gov. Robert D. Orr (R), 62, seems sure to trounce industrialist John A. Hillenbrand II (D), 48, and succeed popular retiring Gov. Otis R. Bowen (R).

In this Republican year, Sen. Birch Bayh (D), 52, is fighting a nasty, no-holds-barred battle against Rep. Dan Quayle (R), 33, in an effort to become Indiana's first four-term senator. Quayle, a two-termer from Fort Wayne, was much less well known, but took advantage of Bayh's September absence from the state and the airwaves (during his chairmanship of the Billy Carter investigation) to close the gap.

With both sides exploiting such emotional issues as gun control and abortion, Bayh has struck back with TV ads decrying Quayle's oil industry support and a pamphlet claiming the Birch Society and the Klan are among the groups "funneling enormous . . . support to defeat Birch Bayh." Republicans accused him of "contemptible politics," but Bayh has been as tough in his personal comments on the young rival he called a "freshman law student." The polls are very tight, but with registration down in heavily Democratic Lake County (Gary) and Bayh dependent on a big turnout, Democrats have a sinking feeling about the tossup race.

This is even more true of House Majority Whip John Brademas (D), an 11-term incumbent from recession-plagued South Bend, whose nemesis is John P. Hiler (R), a 27-year-old businessman. Hiler claims a 12-point lead, but Democrats insist Brademas is climbing back and registration is up here. Other less threatened Democratic incumbents include Reps. Floyd Fithian (D) vs. State Sen. Ernest Niemeyer (R); David W. Evans (D), in his third challenge from David G. Crane (R); and Phil Sharp (D), in his third contest with former state senator William G. Frazier (R). The GOP has some worries about Daniel R. Coats (R), Quayle's district aide, succeeding his old boss in a House contest with attorney John D. Walda (D). IOWA (8)

TODAY'S DES MOINES REGISTER Iowa poll showed a slight improvement for Carter from early October, with Reagan leading 45.8 to 36.7 and Anderson down 4 points to 8.1.

But the big news is that the seesaw Senate battle between Sen. John C. Culver (D), 48, and Rep. Charles E. Grassley (R), 47, has swung slightly in Grassley's direction. Grassley led 49.0 to 45.3, after trailing 43-48 earlier in the month. Friday night's final TV debate was rated a draw, and both sides clearly know Culver's chances of winning a second term in this classic liberal-conservative struggle depend on getting out the vote.

In House races, Republicans claim an outside chance that Donald Young (R), a Des Moines doctor, can upset 11-term Rep. Neal Smith (D). The close fight for Grassley's traditionally Republican House seat, between former state representative Cooper Evans (R) and Black Hawk County Commissioner Lynn Cutler (D), was clouded by the heart attack death last week of Cutler's husband. Until then, Democrats hoped for an upset, and some think it still might happen. KANSAS (7)

THE OCTOBER POLL by the Topeka Capital-Journal showed Reagan holding a 19-point lead over Carter, and Sen. Bob Dole (R), 57, with a 41-point landslide over former state senator John Simpson (D), 46, a former Republican who switched parties in a vain effort to deny Dole a third term.

In the Republican tide, the GOP is expected to retain its 4-1 House advantage, including the seat of retiring Rep. Keith G. Sebelius (R), whose former aide Pat Roberts (R) is leading State Rep. Phil Martin (D). Freshman Rep. Jim Jeffries (R) has widened his margin slightly in the polls over Sam Keys (D), former husband of ex-Rep. Martha Keys (D), who lost to Jeffries in 1978, and veteran Rep. Larry Winn Jr. (R) appears too entrenched for the challenge of Dan Watkins (D), a top Democratic organizer. MICHIGAN (21)

'I WOULDN'T BET more than $1 either way," said one veteran Michigan politico Friday and that sums up the situation. Republicans claim Reagan was 4 points ahead even before the debate boosted his stock here, as elsewhere, but they were worried enough to bring Reagan and former President Ford back again yesterday. Top Democrats say the mobilization of labor, black and party organizations has been more thorough here than in any other state, and think that will do the job -- despite Reagan efforts to exploit auto industry unemployment. Bet Reagan -- but only $1.

The likeliest House turnover could come in freshman Rep. Don Albosta's (D) battle with State Sen. Richard J. Allen (R), but freshman Rep. Howard Wolpe (D) is also hard pressed by businessman James S. Gilmore (R). Democrats must worry too about the seat of retiring Rep. Lucien N. Nedzi (D), where State Rep. Dennis M. Hertel (D) is battling TV talk show host Vic Caputo (R). Retired judge George W. Crockett Jr. (D) will take the Detroit seat that belonged to convicted ex-representative Charles C. Diggs Jr. (D). MINNESOTA (10)

WITH A 4-POINT Carter lead in a mid-October Minneapolis Tribune poll, reports in both camps are that Anderson's decline and Mondale's home-state campaigning are pointing the president toward a win smaller than his 1976 margin but still secure.

Republicans think they will pick up the seat of retiring Rep. Richard Noland (D), where Vin Weber (R) is opposing Archie Baumann (D) in a battle between two political-aides-turned-candidates. They also claim Rep. Arlan Stangeland (R) is leading in his rematch with former state representative Gene Wenstrom (D), but Democrats have not given up on either fight. MISSOURI (2)

ONE BEMUSED national campaign aide says polls indicate the lead has shifted five times in Missouri since September and the latest polls show it achingly close.The St. Louis-Dispatch-KMOX poll had it Reagan 38-37, and the St. Louis Globe-Democrat had it Reagan 44-42. Carter will have the last word in a visit Monday, and, despite the polls, has a Democratic tradition going for him.

With major newspaper endorsements and hard-hitting ads, ex-governor Christopher (Kit) Bond (R), 44, has moved ahead in his rematch with Gov. Joseph P. Teasdale (D). The latest poll puts the margin at 10 points.

Sen. Thomas F. Eagleton (D), 51, appears to have withstood the personal publicity for the unsubstantiated charges of business and personal scandal aired in a trial in which his niece was convicted of extortion. The poll shows him 21 points ahead of St. Louis County Executive Gene McNary (R), 45, in his bid for a third term.

In the House, a switch is expected in the district of retiring Rep. Richard H. Ichord (D), where State Rep. Wendell Bailey (R) is leading State Rep. Steve Gardner (D). Reps. Harold L. Volkmer (D) and Bill D. Burlison (D) have much stronger than usual challenges but should prevail. NEBRASKA (5)

REAGAN IS A CINCH, but Republican hopes of picking up the seat of retiring Rep. John J. Cavanaugh (D) have hit a snag. Hal Daub (D), an Omaha businessman, was running comfortably ahead of County Commissioner Richard M. Fellman (D), but a flap over a "keg party" he sponsored for high-school-age campaign volunteers was followed by charges in the archdiocesan newspaper that Daub followers had "packed" a meeting of a right-to-life organization to secure its exclusive endorsement. Daub has been thrown on the defensive, and the race is in doubt. NORTH DAKOTA (3)

WITH THE PRESIDENTIAL race and a Senate contest well in hand, Republicans are trying to annex the governorship and hold a House seat as well -- but a split verdict is likely.

Reagan is comfortably ahead, despite late Democratic efforts to turn the grain deal with China to Carter's advantage. Rep. Mark Andrews (R), 54, is far enough in front of Kent Johanneson (D), 43, lawyer and oil broker, in the race for the seat of retiring Sen. Milton R. Young (R) that he is helping out on other races.

Gov. Arthur A. Link (D), 66, is being hard pressed by Attorney General Allen I. Olson (R), 41, in his fight for a third term, but Tax Commissioner Byron L. Dorgan (D) has a bit more of an edge on State Sen. Jim Smykowski (R) in the fight for Andrews' House seat. OHIO (25)

CARTER CARRIED Ohio last time by 11,116 votes and has been hanging in for another possible squeaker. His own polls gave him a slight pre-debate lead and GOP surveys after the debate could move Reagan no more than a couple of points in front. Today the Akron Beacon-Journal released a poll taken from Monday through Thursday showing it Reagan 43, Carter 39 and Anderson 6 -- a net 7-point improvement for Carter since a similar poll three weeks earlier. aAs in 1976, Carter is weaker than the normal Democrat in the Cleveland area and stronger in southern Ohio. Call it a tossup, with a tiny Reagan edge.

No hedging on the Senate race, however. It is freshman Sen. John Glenn (D), 59, by a landslide over State Rep. James E. Betts (R), 46. The House races favor a GOP pickup or two. Freshman Rep. Lyle Williams (R) is holding on against State Sen. Harry Meshel (D) in troubled Youngstown. The GOP thinks it can beat veteran Rep. Thomas L. Ashley (D) with Toledo attorney Ed Weber (R) and perhaps pick up the open seat of retiring Rep. Charles A. Vanik (D) where ex-probate judge Joseph J. Nahra (R) faces State Rep. Dennis E. Eckart (D). SOUTH DAKOTA (4)

REAGAN HAS the state in hand, but the voters' eyes are on the rough, free-spending contest between Sen. George McGovern (D), 58, seeking a fourth term, and Rep. James Abdnor (R), 57. In the final phase of a no-holds-barred battle that has been building for over a year, each camp has charged the other with campaign law violations.

Abdnor has been the betting favorite from the start, and last week claimed to have opened up a 14-point lead. But McGovern claims over 50 percent of the decided voters are with him and has Abdnor outspent 2 to 1. Antiabortion groups are leafletting for Abdnor this weekend, but McGovern's local organization is the most thorough he has ever assembled. Abdnor rates a narrow favorite.

Former state senator Clint Roberts (R) is expected to beat Public Utility Commissioner Kenneth D. Stofferahn (D) for Abdnor's House seat. u WISCONSIN (11)

REAGAN HAS SHOWN a narrow but consistent 3-4-point margin in private and public polls, and he bolstered his blue-collar bid with a Friday stop in Cudahy. But insiders in both parties hesitate to call the state his for three reasons: a hunch that the Anderson vote may dip further in Carter's direction; the impact of yet one more visit by the popular Minnesotan, Mondale, and election day registration, which normally favors the Democrats. Carter won the state by 35,000 votes last time -- and just might again.

Sen. Gaylord Nelson (D), 64, looks like a comfortable winner for a fourth term over ex-Rep. Robert W. Kasten Jr. (R), 38, who threatened briefly in September but then faded. The prospects are less comfortable for Rep. Robert W. Kastenmeier (D), hard pressed in his rematch with yoyo manufacturer James A. Wright (R). Rep. Alvin Baldus (D) is a slight favorite over former state representative Steven Gunderson (R).