LOUISVILLE, NOV. 3 -- Republican hopes of expanding their beachhead in southern and border states were set back tonight as Democrats won gubernatorial races in Kentucky and Mississippi.

Wallace Wilkinson, a self-made millionaire and political novice, rolled to a landslide victory over his underfinanced opponent, Republican state Rep. John Harper, in one of the most lopsided races in Kentucky history.

With 97 percent of the precincts reporting, Wilkinson won with a record 65 to 35 percent split.

Mississippi State Auditor Ray Mabus, facing a tougher challenge, was beating Republican businessman Jack Reed by a smaller, but still decisive, margin. With almost half of the precincts reporting, Mabus led 55 to 45 percent.

Reed, the chairman of a reform committee that overhauled the state's school system, was viewed as the strongest GOP candidate in memory. But no Republican has won the Mississippi governor's office since Reconstruction.

Reed, 63, closed in on Mabus, a Harvard-educated political reformer, during the final weeks of the campaign by charging that the Democrat's plan to raise teachers' salaries would hit taxpayers in the pocketbook.

"Ray is going to raise your taxes. No Mabus about it," said one 10-second television spot.

Only three states held off-year elections this year. Republicans, who picked up governorships in four southern states last year, hoped they would demonstrate continued party realignment in southern and border states.

But Rep. Robert L. Livingston Jr., the GOP hopeful in Louisiana, was beaten by two Democrats, Rep. Buddy Roemer and Gov. Edwin W. Edwards, in the Oct. 24 primary. Edwards dropped out, handing Roemer the governor's chair.

"This year shows Republicans have been blowing smoke about party realignment in the South," said Chuck Dolan, executive director of the Democratic Governors Association. "They only win when Democrats beat themselves."

It is hazardous to make sweeping generalizations about governors races, however. They are waged over local issues and involve local traditions and personalities.

About the only common thread this year is that Democrats used vaguely populist themes in Louisiana, Mississippi and Kentucky.

In Kentucky, Wilkinson beat former governor John Y. Brown Jr. and Lt. Gov. Steve Beshear in a stunning upset in the Democratic primary by running as a nonpolitician who would bring new ideas to state government, including a lottery to help the elderly and give Vietnam veterans a bonus.

Wilkinson, 45, who spent $2.3 million of his own money in the primary, was considered such an underdog that neither the press nor his opponents paid much attention to him then.

That changed dramatically after the primary, and he has been plagued for months with troubling questions about his business deals, taxes and relationship with Italian investors.

Many of the questions centered on a used-textbook firm, Wallace's Book Store, that is at the heart of his $37 million-a-year business empire that includes banking, real estate, coal and hotel interests.

The firm was forced to pay back taxes and its president, Wilkinson's brother-in-law, pleaded guilty to charges of wiretapping and rolling back odometers on company-leased cars.

Harper, 57, called Wilkinson "a weasel" and "a sleaze." But he never emerged as a credible candidate. He entered the race only after Larry Forgy, who had been groomed for the contest, withdrew unexpectedly. Ponderous and inexperienced, Harper raised only $225,000, compared to $6 million for Wilkinson.

Wilkinson carried all but a handful of counties and his victory margin set a record.

Harper conceded early, portraying himself as a sacrifical lamb. "I was out there. And others were not," he said. "I don't have any regrets. We're proud of our party. We're going to build our party and just say 'Look out next time.' "

The campaign left many voters disgusted, and turnout was light today.

Seventy-six percent of voters responding to a straw poll conducted Monday by a Louisville television station said they wished they had another candidate to vote for.

In Mississippi, Mabus, 39, was counting on a large turnout from black voters under warm and sunny skies to help him defeat Reed.

A statewide poll released last week had Mabus leading 49 to 38 percent, including 78 percent of the black vote. About one-third of the state's 2.5 million residents are black.

"This election is about whether Mississippi is going to stay with the past -- the status quo -- or whether we're going to change and make a future we're all proud of," Mabus said. "I think we're ready to make basic changes, and I believe the people feel that way, too."

Mississippi Gov. William A. Allain declined to seek a second term although he pushed through an amendment that for the first time in a century allows back-to-back terms.