The Midwest turned out to be one of the most politically volatile regions of the nation Tuesday, as voters ousted four out of the six incumbent governors who sought reelection.

Sitting governors were turned out of office in Minnesota, Kansas, Nebraska and, apparently, in Michigan. Only in Wisconsin and Iowa did the state chief executives -- both Republicans -- retain their posts on a day in which voters vented their anti-incumbent sentiments more in the direction of state capitols than toward Washington.

In the 10-state region, only one senator, Rudi Boschwitz (R-Minn.), lost. For the most part, House seats also remained safe, though sitting members of congress were upset in Minnesota, Missouri, Indiana and Wisconsin.

However, many of the federal races in which incumbents emerged triumphant proved somewhat closer than had been predicted.

While personal attacks, revelations of scandal, and ethics questions were issues in many states -- most spectacularly in Minnesota -- so were more substantive concerns about the economy, jobs, taxes and education.

The increasingly complex political interplay of the abortion issue was evident throughout, and was illustrated by the loss of Kansas Gov. Mike Hayden, an abortion rights Republican, to Joan Finney, an anti-abortion Democrat. In Minnesota, Rep. Arlan Stangeland (R) was unseated by a Democrat favoring a constitutional amendment to limit abortions.

In the race for the governorship of Illinois vacated after 14 years by James R. Thompson (R), a Republican favoring raising taxes defeated a Democrat who called for lowering them. ILLINOIS

In the race to replace retiring Gov. James R. Thompson (R), Illinois voters kept the GOP in the state house with Jim Edgar (R) picking up 52 percent of the vote. Neil Hartigan (D) received 48 percent, with 98 percent of precincts reporting.

The tax issue dominated the race. Republican Edgar, unlike most Republicans nationwide, backed higher taxes -- favoring continuing an income tax surcharge for education that Hartigan opposed. Traditional bases of support were weak for both candidates as Hartigan partisans in Chicago stayed home and Edgar polled about one-quarter of the traditionally Democratic black vote but made a weak showing among Republicans in his downstate home turf.

Incumbent Sen. Paul Simon (D) easily fended off attempts by opponent Rep. Lynn Martin (R) to paint him as a liberal out-of-step with his constituents. Simon won handily with a 65 to 35 percent marghin.

Martin imported GOP campaign consultant Roger Ailes, but many found the candidate too spiteful. She began her campaign effort by referring to voters in southern Illinois as "rednecks." Unlike Hartigan, Simon held on to traditional Democratic voters, picking up 91 percent of the black vote and two-thirds of the women's vote.

Incumbents kept all House seats. Voters returned such well-known congressional figures as Gus Savage (D), Frank Annunzio (D) and Ways and Means Committee Chairman Dan Rostenkowski (D). But Democrat John W. Cox beat state representative John W. Hallock Jr. for the seat vacated by Martin. INDIANA

The good news for Republicans was that their recently appointed senator, Daniel R. Coats, won his first statewide election since being tapped to take the seat vacated by Vice President Quayle.

The bad news was that Democrats won two high-visibility contests, including the capture of an eighth House seat. The state has 10. In the 3rd Congressional District, Timothy J. Roemer (D), a 33-year-old with strong Washington ties, defeated Rep. John Hiler (R). And in a contest on which almost as much money was spent as on the Senate race, Joseph Hogsett (D) edged out Indianapolis Mayor William H. Hudnut (R) to retain his post as secretary of state, an Indiana stepping stone to higher office.

Roemer, a former aide to one-time House majority whip John Brademas (D) and son-in-law of Sen. J. Bennett Johnston (D-La.), began as a mild underdog. But Hiler, who has survived three hard-fought challenges, finally succumbed in a year in which incumbency was the margin in tight races.

In the Senate election, challenger Baron Hill (D) ran a feisty campaign that lampooned Coats's massive use of mail paid for by taxpayers. But Coats outspent his opponent handily, was never in serious trouble and won by a 54 to 46 margin. In the 5th Congressional District, Rep. Jim Jontz (D) turned back GOP hopes to pick up a House beat by beating John A. Johnson. IOWA

Iowa had never sent a Democrat to the Senate twice in a row. But Sen. Tom Harkin lifted the two-term curse, defeating Rep. Tom Tauke (R) by a convincing 54 to 46 percent. Harkin finally pulled ahead in the final weeks of a hard-fought campaign.

As befitted a race between two men from the halls of Congress, it focused on the issues -- in particular abortion, the economy, and government spending. But from time to time, it also got personal. Tauke, a six-term House member, accused Harkin of running ads distorting his position on abortion, and criticized his votes for catastophic-health insurance and higher Social Security taxes. Tauke was criticized for taking a pay raise he had opposed in 1989.

But external circumstances may have been as important in enabling Harkin to make history, political observers said. The emerging recession and the Bush administration's intervention in the Persian Gulf did not strengthen the Republican cause in a state that feels the economic pinch and is wary of foreign involvements.

In the race for governor, two-termer Terry E. Branstad (R) beat state House Speaker Don Avenson (D) by a 61 to 39 margin. The race focused on their records and economic development in Iowa. Abortion was also an issue, with Branstad the antiabortion candidate and Avenson standing for abortion rights.

While Tauke lost, the GOP appeared to have held the 2nd Congressional District seat he vacated by a razor-slim margin. Jim Nussle (R), 30, edged Eric Tabor (D), 35. KANSAS

Another upset in the state house. Taxes and abortion were major issues in the governor's race, with less-than-predictable voter draws. Both incumbent Gov. Mike Hayden (R) and State Treasurer Joan Finney (D) pitched a reduction in property taxes with offsetting tax increases in other areas. But Finney maintained a stanch antiabortion stance, initially even for rape victims, while Hayden favored abortion rights. Finney pulled ahead of Hayden for a 53 to 47 percent win.

Sen. Nancy Kassebaum (R) won by a hefty margin for a third term over political unknown Dick Williams (D). With 99 percent of the precincts tallied, Kassebaum had 74 percent of the vote to Williams's 26 percent. In the race to replace retiring Rep. Bob Whittaker, banker Dick Nichols (R) won 59 percent of the vote to defeat rancher George Wingert (D), who collected 41 percent. MICHIGAN

In the first apparent upset of an incumbent governor since 1962, state Senate Majority Leader John Engler (R), with a 19,000-vote lead, declared victory yesterday over Gov. James J. Blanchard (D). Blanchard has not conceded, but several media outlets have called the race in Engler's favor.

Engler, who received three campaign visits by President Bush, was the antiabortion candidate while Blanchard favored abortion rights. Blanchard led an early attack on his challenger, only to get into some minor scrapes over a prison-related ad that some criticized as racist, the release of a controversial book by his ex-wife about their private life and a fracas over his dumping of running mate Martha Griffiths.

Blanchard may have been hurt by low voter turnout in the traditional Democratic strongholds of Detroit and surrounding Wayne County.

Sen. Carl M. Levin (D) was returned to Washington with a 58 to 42 percent win over challenger Rep. Bill Schuette (R). Levin built a big campaign war chest against Schuette's family fortune and was able to rebut the Schuette's criticism his liberal record.

"It's not as though there was an across-the-board 'throw the bums out' attitude," said State Republican Party press secretary Rusty Hills.

Schuette's appointed successor, state Rep. David Camp (R), won with a nearly 2 to 1 lead over political novice Joan Dennison (D). The delegation adds a woman to its ranks with the overwhelming victory of Barbara-Rose Collins (D), a city council ally of Detroit Mayor Coleman Young, over Carl Edwards (R). The seat was vacated by retiring Rep. George W. Crockett Jr. MINNESOTA

Anti-incumbent fever took a heavy toll here Tuesday. The victims were a governor, a senator and a six-term congressman.

Even one of the most chaotic Republican challenges in the nation was not enough to save 10-year incumbent Gov. Rudy Perpich (D), who lost to state auditor Arne Carlson (R) by 51 to 49 percent.

Carlson was tapped to run against Perpich in the final days of the campaign, after nominee Jon Grunseth (R) quit following allegations that he had an extramarital affair and had gone swimming nude with teenage girls.

Meanwhile, Sen. Rudy Boschwitz (R), running a conventional campaign, was upset by one of the most unconventional challengers on this year's national stage, college professor Paul Wellstone. Wellstone, campaigning with references to "Camelot" and the 1960s, promoted a multibillion-dollar health care system while Boschwitz collected endorsements from President Bush and Senate Minority Leader Robert J. Dole (R-Kan.).

Wellstone -- who, like Boschwitz, is Jewish -- was a co-chairman of Jesse L. Jackson's 1988 presidential campaign. Early assessments gave him little hope of unseating Boschwitz, who regularly had home state popularity ratings in the 60 and 70 percent range. But Wellstone's campaign apparently caught the wave of anti-incumbent sentiment after this year's budget deadlock, and tapped into a strong strain of Minnesota idealism. His victory margin was 52 to 48 percent.

Political observers said it remains to be seen whether Wellstone's left-of-center politics will make headway in a Senate chamber where compromise and hard-nosed deal-cutting are needed to move legislation.

In still another anti-incumbent upset, Minnesota voters ousted Rep. Arlan Stangeland (R) and replaced him with Collin Peterson (D), who supports the death penalty and a constitutional amendment limiting abortions. Stangeland was stung by reports that he used his official credit card to make numerous telephone calls from the home of a female lobbyist. Democrats now control six of Minnesota's eight House seats. MISSOURI

There was no election for governor or senator to pump up Missouri voters, but in the end there was excitement enough as Joan Kelly Horn (D) appeared to have edged out incumbent Rep. Jack Buechner (R) in one of the nation's closest contests.

With all the votes counted in the 2nd Congressional District, Horn -- a veteran political consultant turned candidate -- claimed victory by a 52-vote margin. The Board of Elections reported 94,300 votes for Horn and 94,248 for Buechner. Buechner was demanding a recount.

Horn, 55, who has been advising candidates in the St. Louis area for years, waged a biting, personal campaign, charging Buechner with foreign junketeering and raising questions about his outside earnings. Buechner denied any impropriety.

Assuming Horn's victory holds up, it will rank as one of the major congressional upsets. In August she was given little chance to win. Among other disadvantages, her abortion-rights stance was seen as a drawback in the blue-collar communities. But deterioriating economic conditions in defense plants may have hurt the incumbent.

The other seven House incumbents from Missouri, including Majority Leader Richard A. Gephardt (D), won reelection. NEBRASKA

Ben Nelson (D) narrowly defeated incumbent Gov. Kay Orr (R), the state's first woman governor. With all but 9,000 absentee ballots counted, Nelson captured 286,608 votes to Orr's 281,827. Orr, the target of a tax revolt, had fought back with ads about Nelson's financial ties to a company that deals in junk bonds. The race was also targeted by the Democratic Governors' Association as a potential gain for the party.

Sen. J. James Exon (D), a conservative, retained his seat with a wide 59 to 41 percent victory over challenger Hal Daub (R), a former House member. Daub was hurt by supporter and former Texas senator John G. Tower's remark that Exon was "one of the two or three biggest boozers" in the Senate. Exon, who denied the rumor, shot back by alluding to rumors of domestic violence in Daub's family.

The Republicans retained the House seat vacated by Rep. Virginia Smith as Bill Barrett, speaker of the unicameral legislature, scored a 51 to 49 percent victory over Sandra K. Scofield (D), a teacher and farmer. Meanwhile, Reps. Doug Bereuter (R) and Peter Hoagland (D) won reelection.

Voters also rejected a proposed constitutional amendment to limit state and local spending increases to 2 percent annually. NORTH DAKOTA

Rep. Byron Dorgan (D), North Dakota's sole House member -- and sole candidate for national office -- felt the anti-incumbent mood this year.

His 71 percent victory in 1988 was sliced by 5 percentage points, to 66 percent. The loser was businessman Edward Schaefer (R). OHIO

This was not a state in which the results of the major race -- the gubernatorial victory of George Voinovich (R) -- allowed pundits to draw sweeping conclusions.

The incumbent, Gov. Richard F. Celeste (D), was not running, and Voinovich and his opponent, Anthony Celebrezze Jr. (D), were both well-known Ohio incumbents in their own right. Celebrezze is state attorney general. Voinovich is a former mayor of Cleveland.

What materialized was an old-fashioned, hard-fought Midwestern campaign mobilizing the wards and stressing issues such as health care, the economy, jobs and education -- with a dash of negative campaigning thrown in.

Voinovich, who is credited with leading Cleveland out of financial default during his 10-year administration, had the edge in experience. But Celebrezze, whose father was also a five-term mayor and served as secretary of health, education and welfare under President John F. Kennedy, received a respectable 46 percent of the vote.

In congressional battles, Cincinnati Mayor Charles (D) edged out former mayor J. Kenneth Blackwell (R). But the GOP held onto two vacant seats it had previously held. SOUTH DAKOTA

Billed as a shoo-in for a fourth Senate term earlier this year, Sen. Larry Pressler (R) ended up in a horse race.

With most of the votes counted, he had 52 percent, to 45 percent for Ted Muenster (D), a Sioux Falls businessman. That was much closer than the 30-point deficit that polls said Muenster began with.

In July, Common Cause disclosed that Pressler ranked 43nd in the Senate in campaign receipts from savings and loan groups. In a debate with Muenster, Pressler said he received $2,000 to $3,000 from the thrifts, but subsequently retracted and said the amount could have been $10,000. Muenster also attacked Pressler for breaking a 1974 pledge not to accept speech honoraria. Pressler said he made that pledge only while serving in the House.

In the race for governor, heavily favored incumbent George S. Mickelson (R) easily defeated former state senator Bob Samuelson (D), 59 to 41 percent. WISCONSIN

Gov. Tommy G. Thompson (R), who has wide appeal in this liberal state, won reelection by 58 to 42 percent over Assembly Speaker Tom Loftus (D). Rep. Robert Kastenmeier (D), chairman of the House Judiciary subcommittee on courts and a 32-year House veteran, lost to former Madison sportscaster Scott Klug (R).