It was lunch hour at the Westinghouse defense research plant in Anne Arundel County and Howard Greenebaum, a candidate for the Democratic nomination in the 4th Congressional District, handed his brochure to a crew-cut technician seated in the cafeteria who scanned it and asked Greeenebaum where he stood on defense spending.

Without visible hesitation, Greenebaum replied there should be cuts. Then Greenebaum, oblivious to the tightening lines on the technician's face, asked the man for his thoughts on defense spending.

"Where the hell do you think I'm working and where the hell do you think you are?" fumed the technician. "You're not going to make it here. You're not going to beat her."

So goes sentiment in the district that has been dominated for five two-year terms by Republican Marjorie Holt, one of the most electorally safe members of Congress and a hawkish supporter of defense contracts. Holt hasn't had a Republican primary opponent since she first ran in 1972. In 1980, she trounced her Democratic opponent by a 72-28 percent margin.

On the eve of the Democrats' Sept. 14 primary, then, the question politicians are asking is not who's going to win the nomination, but why anyone would want to tangle with the Republican with the gray bouffant hairdo.

This summer, four Democrats have been taking on Holt: former delegate Patricia O'Brien Aiken of Annapolis, former jewelry chain store owner Greenebaum of Annapolis, retired Army major Milton W. Showell of Camp Springs and former teacher Kent Sullivan of Laurel.

"Someone has got to carry the banner," explained Aiken, 60, the candidate party leaders privately predict will win the nomination. "While I had no intention of running, I decided we couldn't give her a free ride this time. . . . At best, I have a 15 to 20 percent chance of winning."

Aiken, a former state delegate, agreed to run in February after party leaders failed to find a more prominent candidate for the only congressional seat in the state held by a Republican.

"It's just a foregone conclusion down here that Marjorie is going to win," said Anne Arundel County State's Attorney Warren Duckett, a Democrat, who has considered running for the seat that spans the whole of Anne Arundel, dips into southern portions of Prince George's County and includes a bit of Howard County.

"I have a lot of close family friends that say to me, 'Warren, we love you, but if push comes to shove and you run against Marjorie, we'll vote for Marjorie,' " Duckett said.

"Marjorie is an institution here. How do you beat that?"

A serious race against Holt would cost at least $150,000, party officials estimated. Thus far, for the primary, two candidates, Aiken and Showell, have raised less than $5,000 each. Sullivan has raised no money and said he has no intention of doing so. Greenebaum said he has spent $60,000--"about" $58,000 from his own pocket.

Despite the odds and heat of summer, the four Democrats have been stumping tirelessly at campaign forums, delivering two-minute speeches and passing out leaflets at shopping centers and business cafeterias.

Why? Simple, the candidates say: they don't like the way Holt votes. She's just too conservative for them.

Holt received an overall voting rating of 95 percent from the American Conservative Union and a zero last year from the National Council of Senior Citizens.

Running against Holt, for these candidates, is running against too much spending on defense and too little on social programs.

"I'm seriously concerned for the future of this country and the effect Reaganomics is having on people," Aiken said. Social security must be protected and removed from the "unified budget" process and more money put into domestic social programs and public works programs, she said.

Greenebaum, 52, who party leaders say will give Aiken the best challenge, said of Holt: "She's wrong on the issues. She's wrong on the way she votes. . . . Everywhere I go, I'm finding people who are being hurt financially by the types of things she does." Greenebaum closed his three Baltimore jewelry stores in January to spend full time running for Congress.

He contended that billions of dollars in defense spending could be saved if there were one combined military service and more supervision of weapon development. Some of this money then could be used to expand job-training programs for the unemployed.

Showell, 46, the former Army major, and Sullivan, 38, an independent truck driver with a master's degree in education administration, both attack Holt on one issue. Showell complains that Holt, a ranking member of the House Armed Services Committee, has not favored a ceiling on defense spending, while Sullivan calls it "insane" Congress has not enacted a nuclear arms freeze.

Valid as the criticisms might be, Democrats say, they are not enough to unseat Holt. Despite a 2 1/2-to-1 voter registration favoring the Democrats and the district's proximity to Baltimore and Washington, the 4th District is more Dixie Democrat than northern urban.

"There's no doubt about it that when it comes to Mrs. Holt we have a problem," said Anne Arundel County Democratic Central Committee chairman William Waldecker. "She votes terribly, but no one seems to notice. She has this beautiful constituent service. If you call her office and say I need a pothole fixed or my Social Security check is late, she'll see to it that someone on her staff gets to it that day. It's incredible, and hard to beat."

Party leaders had hoped to change their bleak history in the congressional race this year with basketball star Tom McMillen, who has a home in Crofton. But those aspirations were dashed when McMillen, who has made no secret of his political ambitions, announced he would play the remaining two years of his contract with the Atlanta Hawks.

At that point, Aiken and her three opponents stepped in, and much of the interest on the national, state and county level dropped out. A spokesman for the national Democratic Congressional Campaign Committee said they have no plans to target the race or fund it. "Let's see, I wouldn't want to mislead anyone to think this is one of our top four or five races in the country," Evan Zeppos said.

Aiken, who has raised little money, nonetheless has one of the best campaign organizations, having recruited volunteers from her more than 20 years in local politics. An Aiken campaign worker has been placed in most of the more than 150 precincts. Aiken appears to have the private support of state and county leaders, who say they give her a slight edge over Greenebaum--she's received the endorsement of the Baltimore News-American--but say that advantage may dwindle quickly if Aiken does not raise more money quickly, a feat Aiken said is unlikely.

Greenebaum, who has splashed his name across newspapers and television and has prepared 18 one-minute telephone tapes explaining his views on issues ranging from abortion (he's pro-choice) to draft registration (he supports it), scoffs at reports that Aiken may have an edge in the race.

"I've slaughtered her. She hasn't any money," Greenebaum said. Greenebaum, who was chairman of presidential hopeful John Anderson's speakers' bureau, said he is funding his campaign with money from his jewelry stores.

Greenebaum, who was endorsed by the Baltimore Sun, appears undaunted in his bid to unseat Holt. Campaigning 15 hours a day, he said, he concentrates his attacks on Holt and not his Democratic opponents. He received the endorsement of the state AFL-CIO in late July but failed to convince many party leaders to lend their weight to his campaign.

In an area where friendships are as important in political races as money, Greenebaum also has privately ruffled the feathers of a number of state and county party leaders who believe he has not paid his dues on the local level: this is his first bid for an office. Greenebaum, they add, appears unnecessarily arrogant and defensive.

"When Howard told me he was going to run for Congress, my first question was why? Here was this person no one had heard of," said one Democrat high in the state party organization, "He said, 'I have ideas and I have the money.' Well, a lot of people have ideas, but they usually write letters to the editor and don't run for Congress."

Candidate Sullivan laughs when discussing his chances. "I have about a one-in-four chance of winning the nomination, and it would be a miracle if I beat Holt. I assume she will wipe every single one of us off the board," he said.

Sullivan challenged 6th District Rep. Beverly Byron in 1980 and, in his words, "She cleaned the clocks of all of us." Sullivan abandoned teaching to take up driving when "he got sick of it and wanted to do something else."

His reason for running against Byron and then Holt?

"When the building is burning, I feel like throwing a few buckets. . . . Frankly, they are the two members of Congress whose voting records I don't like."

Candidate Showell, who professes that Holt is beatable, is said by party regulars to lack campaign money and name recognition. He lives in Prince George's County, but more than half of the 225,000 registered voters in the 4th District are in Anne Arundel.

In addition to favoring a ceiling on defense spending, Showell said he is concerned with fighting racial, sexual and religious discrmination.