A Klansman will be running for Congress in southern California this November, a result, political observers believe, of voters fears about the mounting influx of illegal aliens from Mexico and Southeast Asian refugees.

California Ku Klux Klan Director Tom Metzger won the Democratic nomination in the state's 43rd District last Tuesday by a margin of 318 votes out of 87,000 cast in a three-way race.

"Metzger took after the Asians, the Cubans and the undocumented aliens and it worked," said Ed Skagen, a retired labor leader and San Diego Democratic Party chairman, who ran second. "His election is a repudiation of knee-jerk liberalism. It's a revolt against what is."

Skagen and other local activists tried to warn top party officials and potential campaign contributors about an activist tide among the predominantly working-class and middle-class whites in the district, which runs from the posh seaside suburbs of San Diego and the Pendleton Marine Base in the east all the way to the Arizona border.

But their warnings went unheeded, for the most part, by top Democratic officials, as well as Jewish, Hispanic and liberal leaders in the area.

"The big leaders told us to wait until after the primary. They wouldn't take Metzger seriously," said Sarah Lowery, coordinator of the Carter for President Campaign in San Diego County and a strong Skagen supporter. "I tried to reach (state Democratic party chairman Richard) O'Neill but he wouldn't return my call. The leaders are so out of touch. They never thought it would happen."

Cut off from traditional Democratic funding sources, Skagen was forced to run a bare-bones campaign on a $3,000 budget -- $2,500 of which came out of his own pocket. Metzger spent around the same amount of money but was aided by a gusher of free publicity concerning his campaign and his prior Klan activities in the area.

Since Metzger's nomination, embarrassed Democratic Party officials, including National Party Chairman John C. White, State Chairman O'Neill, and U.S. Sen. Alan Cranston, have bitterly denounced the Klansman's triumph. Some, including Cranston, have expressed their intention of backing Metzger's Republican opponent, Rep. Clair W. Burgener, in the general election.

Worried over the effects on their image by having a Klan leader as a congressional candidate, some top Democratic officials have tried to paint Metzger's nomination as a fluke rather than as an expression of white backlash within their party.

"It's clear what happened. There were three candidates and the voters were almost evenly split. People remembered Metzger's name from all the publicity, but didn't know what the issues were," said Dennis DeSnoo, executive director of the California Democratic Party. "They pulled the lever for him, but we don't honestly believe they voted really for the Klan -- maybe 2 or 3 percent of the voters, but that's it."

A leading Republican strategist in the district agreed with DeSnoo's assessment of the election and claimed Burgener, a conservative Republican who won reelection in 1978 with some 70 percent of the vote, would have no trouble with Metzger in the fall. "The district is conservative but not that conservative," he said.

Not being taken seriously is something Tom Metzger, a 42-year-old television repair shop owner, has been growing accustomed to. He points out he was given virtually no chance of winning the June primary by the same political leaders who now discount his chances in the fall.

"They're infuriating the voters by ridiculing them," Metzger said. "The media was all over this campaign -- everyone knows who I am. If they didn't, they were a hermit. It just shows the disdain these political leaders have for the common people."

Actions by Metzger and the Klan have drawn wide local coverage over the last several years. Since joining the Klan in 1975, Metzger has won notoriety by establishing a Klan chapter on the Camp Pendleton Marine Base amd by helping organize in 1977 a "borderwatch" along the district's long junction with Mexico.

Federal officials estimate as many as 100,000 illegal aliens live in Burgener's congressional district.It includes a large Hispanic citizen population, more than 30,000 Filipinos and an estimated 20,000 Indochinese refugees.

Metzger and the Klan have directed their anti-immigration racist appeals to the predominantly working and middle-class white residents of small towns in the suburban and rural areas of northeastern San Diego, Riverside and Imperial counties.

"These are people who feel dispossessed, very antiestablishment," observed one long-time suburban San Diego conservative activist who admitted "some sympathy" with Metzger's campaign. "This gave them a chance to protest the thing Metzger's against and they are also against. They are deeply worried about this unlimited immigration which they feel is taking away the jobs, the housing for citizens. This may be the tip of the iceberg."

The Klan attempt to seize on the illegal alien issue was first evident during its 1977 "borderwatch" set up by David Duke, leader of the Louisiana-based Knights of the Ku Klux Klan, to demonstrate his organization's desire to stem the flow of people from Mexico into the state. Metzger, once a member of Duke's organization, has since pulled out and formed his own, California-based Klan.

In recent months the illegal alien issue has grown in prominence throughout the San Diego area, exacerbated by recent news reports about Cuban refugees and Haitians entering the United States through Florida. These recent events, plus the race riots in Miami and fears of a deepening recession, played into Metzger's hands, some observers say they believe.

Metzger considers himself "a populist" in a tradition of Huey P. Long of Wisconsin. He favors the separation of the races, the end of all nonwhite immigration and the establishment of a Christian "theocracy" in the United States, a fact that makes him feel "a great deal of respect" for Iran's fundamentalist leader Ayatollah Ruhollah Khomeini.

The key to Metzger's ideological appeal, he believes, is purely based on race. He says he thinks that, while they won't openly admit it, many white Christian Americans are concerned about having their culture degraded by the growing influence of blacks, Hispanics, Asians, atheistic large corporations and "satanic Judaism."

"A lot of people won't ever say a thing about this in public," Metzger, a native of Warsaw, Ind., said. "They get their revenge in the polling place. nIt has to do with the collective mind. The reasons are deep-seated, almost genetic, of reflex actions. The Anglo population has an instinctive sense of danger and they're trying to find a way to respond to it like a herd of elk forming a circle in self-defense."