Unexpected Vote in Louisiana Seen as New Sign of Discontent : Politics: Johnston’s narrow primary victory joins warning shots fired at incumbents earlier in other states as anger rises among constituents.

For incumbents, this continues to be the year of living dangerously.

On Saturday in Louisiana, three-term Democratic Sen. J. Bennett Johnston narrowly escaped a stunning challenge from state Rep. David Duke--an improbable opponent, whose political baggage included service as the grand wizard of the Knights of the Ku Klux Klan, ties to neo-Nazi and other anti-Semitic groups, fabrication of a war record in Vietnam and embarrassing disclosures that he had once authored a sex manual for women.

Coming just weeks after outsiders won both gubernatorial nominations in Massachusetts and Oklahoma, voters approved a ballot initiative that would limit the terms of politicians, Duke’s success in holding Johnston to a 54% to 44% victory represented another warning shot to incumbents stumbling through the embarrassing wreckage of the federal budget negotiations toward next month’s off-year congressional elections.

“There’s definitely a message bigger than Louisiana here,” said Susan Howell, director of the survey research center at the University of New Orleans. “There is a tremendous amount of anger and frustration among working-class whites, particularly where there is an economic downturn. These people feel left out; they feel government is not responsive to them.”

These feelings of discontent--which may be further crystallized by the deadlock in Washington that has shut down major parts of the federal government--already have erupted in several other states.

Though only one incumbent--scandal-plagued Rep. Donald E. (Buz) Lukens (R-Ohio)--has been defeated in a primary this year, several others have suffered through unexpectedly anxious, if not desperate, hours. Veteran politicians as diverse as Arkansas Democratic Gov. Bill Clinton and Democratic Reps. John P. Murtha of Pennsylvania and Mike Synar of Oklahoma have been shocked by unexpectedly narrow primary victories.

On Saturday, Johnston joined their company. During Election Day, aides confidently predicted that he would win more than 60% of the vote and perhaps as much as two-thirds. But as returns accumulated, they milled through a downtown New Orleans hotel nervous and somber, even after Johnston crossed the 50% barrier needed to avoid a run-off with Duke. Pollsters here said that Duke carried between 55% and 60% of the white vote.

“Voters wanted to send a message,” said Bob Mann, Johnston’s campaign spokesman, “and I guess they did.”

Duke conceded defeat Sunday and backed off his threat to file a lawsuit over absentee ballots cast--but not counted--for state Sen. Ben Bagert, the official Republican nominee. Bagert dropped out two days before Saturday’s primary amid pressure from national GOP leaders who hoped that Johnston would bury Duke in essentially a one-on-one contest.

Much of Duke’s strength derived from racial hostility among whites. But, according to Howell’s surveys, Duke’s support also was attributable to disaffection with government.

In fact, like Alabama Gov. George C. Wallace 20 years ago, Duke portrayed affirmative action, busing and programs “for the rising welfare underclass” as evidence that government has lost touch with the needs of middle-class taxpayers. His audiences invariably agreed.

“People are just tired of being taxed for these welfare programs,” said one woman in suburban New Orleans after voting for Duke on Saturday.

That appeal clearly transcends the South: Boston University President John R. Silber struck some of the same notes while winning the Massachusetts Democratic gubernatorial primary last month--a point that Duke noted in an interview. For that matter, Ronald Reagan successfully used these themes to help win the presidency in 1980.

Duke supplemented those shrill conservative notes with classic outsider appeals against the “Washington Establishment.” Running against a consummate Washington insider, Duke condemned political action committees and called for limits on terms of office.

That message appeals beyond the South, too. Though only Colorado and California will join Oklahoma in voting on term limitation initiatives this year, such measures could sprout across the country in 1992.

“If it passes in California and Colorado, you are going to see grass-roots efforts in a lot of states,” said Charles Black, chief spokesman for the Republican National Committee.

It is difficult to predict how many incumbents actually will be dislodged next month by these persistent ripples of discontent. Though Silber and Duke both struck themes with national resonance, their appeals were amplified by the unusually poor economic situations in their states.

Many analysts caution against generalizing too broadly from these two races--particularly because a number of incumbents who might otherwise be vulnerable lack opponents of sufficient weight to take advantage of the anti-Washington mood.

“It is going to vary from state to state and race to race,” said J. Bradford Coker, president of Maxon-Dixon Opinion Research.

But in these four weeks before Election Day, few incumbents will take much comfort from such predictions, especially now that the collapse of the budget talks has provided challengers with such a compelling symbol of Washington myopia and decay. Heading toward the final turn of the election year, the track is still getting bumpier.