At his typewritter in an obscure office building beside a Woolworth's store in lower Manhattan, an editor whom most Americans haven't heard of routinely cackles at his own zippy prose. Then, five times a week, he dispatches his words to the largest audience of rich and powerful people ever to read an American newspaper.

Robert L. Bartley--editor of The Wall Street Journal, impresario of conservative opinion for the country's only national newspaper--uses his editorial page as an offensive weapon, demanding profound changes in the way the federal government manipulates the economy and deals with the Soviet Union. What makes Bartley worth watching is that much of what he has clamored for has happened. For instance:

* Congress last year passed a whopping tax cut favoring big business, under the theory that businessmen will reinvest their money and revive the economy.

* For six years Bartley and a small army of conservative economists championed this theory--supply-side economics--and helped make it a household expression.

* President Reagan last month denounced the Soviet Union for using chemical and biological weapons in violation of arms-control treaties. Reagan said the Soviets have used "these dread weapons" in Southeast Asia and Afghanistan, and, therefore, all new arms agreement should be approached with care.

* For two years, Bartley's editorials-- with impressive original reporting and bulldog tenacity--have thumped away on the "yellow rain" issue, arguing that the Soviets cannot be trusted in any arms negotiations.

* The Federal Reserve Board has clamped down on the money supply, reducing inflation but at the same time propping up high interest rates that have strangled business borrowing and investment and pushed the country into its worst recession since 1941.

* Bartley has hammered away for years on the need for tight money and continues to warn the Fed not to open up the floodgates to inflation.

Bartley's prose would not, of course, pack the same punch if it were not for Ronald Reagan, whose instincts Bartley claims to share. Bartley's editorial page has been both a billboard and cheering section for the conservatives who swept Reagan into the presidency and forced the federal government to make its sharpest right turn in 40 years. Besides cheering, however, Bartley has fine-tuned conservatism itself.

"Bartley's influence is extraordinary. He provides very significant leadership amongst decision makers in Washington," says economist Alan Greenspan, a former chairman of the Council of Economic Advisers and an outside adviser for Reaganomics. "His influence starts with the president and goes to virtually everyone I know."

"Definitely, The Wall Street Journal editorials are read here," says White House spokesman Larry Speakes, a friend of Bartley. "When they take issue with the president, we do take note."

Bartley, who has presided over Journal editorial policy for a decade, is described by John Tebbel, professor emeritus of journalism at New York University and the author of 40 books on journalism, as "the most influential editorial writer of our time."

Reagan's election has forced Bartley, who made his reputation as an outsider howling about soft-headed liberal rascals, into an unaccustomed role as insider. He has friends and sources throughout the Reagan administration. But the role seems unsuited to his attack-dog writing style. Bartley has proved an uncomfortable, often querulous apologist.

Since the election, the editor has launched an odd crusade, praising Reagan's conservative instincts, yet savaging much of the president's staff. Bartley has warned Reagan to beware of advisers who "are asking him to capitulate to the mindless beast of traditional bureaucratic and pork-barrel pressure."

Bartley bristles whenever Reagan's advisers ask the president to back off from supply-side tax cuts or to cut defense spending. One recent editorial pouted: "Does the Reagan team believe Reaganomics works or not?"

In defending the president's economic package, Bartley has also defended huge budget deficits--a stance some conservatives regard as apostasy. One of Bartley's admirers, John T. McCutcheon, editor of The Chicago Tribune editorial page, says Bartley, "has gone overboard in his defense of Reagan. It seems to me I remember him fighting along with us in the past for a balanced budget."

Criticism doesn't trouble Bartley. He relishes being outrageous.

The editor fortifies his ditorials with what he calls "muzzle velocity." For example: Eastern European countries are "a cruel no-man's land of barbed wire and death." Soviet biological weapons "leave primitive tribesmen choking to death in their own blood." Questions about the leadership ability of Ted Kennedy are "pertinent, since so far as we can see he has never led anything except maybe a regatta off Hyannis."

The president shouldn't trust the Soviets in arms-control talks, Bartley writes, because negotiating with commmunists "is not an after-office poker game. At this saloon they don't check the six-guns at the door. Someone may blackjack you and run off with the pot, or pull a knife or spike your drink with mycotoxins."

In America, Bartley has said, "there aren't any poor people left, you know, just a few hermits or something like that." The nuclear freeze movement, he says, is like the faddish hysteria spawned by the movie "Jaws."

Despite his influence, despite the studied outrageousness of his thinking and his prose, despite a Pulitzer Prize for distinguished commentary, Robert Bartley is not a name- brand journalist. That irks him. Bartley says he envies just one journalist of his generation, the columnist George Will. What he envies about Will is his "public persona."

Bartley is described by friends as "self-confident," by enemies as "arrogant" and by the man who brought him to The Journal as "too big for his britches."

"When I was writing editorials," says Vermont Royster, editor emeritus of The Journal, a Pulitzer Prize winner and the man responsible for putting Bartley in charge of The Journal's editorial page, "I was always a little bit conscious of the possibility that I might be wrong. Bartley doesn't tend to do that so much. He is not conscious of the possibility that he is wrong."

Editorial writers at other major newspapers are less charitable.

"This guy is a radical, not a conservative," says Anthony Day, editor of the editorial pages of The Los Angeles Times. "His page does not reflect a sense of history or compassion. Bartley will extract from what is going on in the world such things as he wants to make a point. His page is humorless, zealous and doctrinaire. It seems to be always denouncing other conservatives for not being true believers."

"Bartley is not your traditional editorial writer," says James M. Perry, a Journal political reporter in Washington. "He is so much tougher, so much more willing to go out and engage in name-calling."

In person, Bartley seems almost meek.

In his ninth-floor Manhattan office, with its sweeping view of the Wall Street financial district, Bartley comes across as friendly, soft-spoken, diffident. He is a thin, brown-haired, small- boned man who wears wire-rim glases, conservative ties and monogrammed shirts. An impish smile, a flat Midwestern accent and an occasional "gee" or "gosh" make him look and sound like a 44-year-old version of what he once was--a very smart small-town boy who always did his homework.

Bartley grew up in the 1950s in Ames, Iowa, a small college town surrounded by cornfields. To understand how Bartley can, all at once, be shy, cocky and convinced that American capitalism will save mankind, it helps to understand what it was like to grow up in Ames.

"We were not seared by fierce poverty, racial tensions, drug abuse, street crime; we were cosseted, gently warmed, transmuted by slow degrees," writes Susan Allen Toth, the author of a memoir of growing up in Ames and a high school classmate of Bartley's. In reviewing Toth's book, Blooming: A Small Town Girlhood, last year in The Journal, Bartley wrote, "Gosh does she have it right."

Teen-agers in Ames were "convinced life was going to be wonderful," Toth writes. There was one black family in town. Divorce was virtually unknown. The closest thing to sex education was a coin-operated condom machine in the men's room of the Hudson service station outside the city limits. If a Protestant married a Catholic there was a "major social upheaval."

Bartley, the son of a veterinarian, attended high school and Iowa State University in Ames. He met his wife, Edith, whom friends describe as "the smartest girl in school," when she was a high school sophomore and he was a senior. Edith was the only girl Bartley ever seriously dated.

Bartley and his wife now live in a carriage house in Brooklyn Heights, a fashionable New York City neighborhood just across the East River from Manhattan's financial district. The Bartleys have three daughters, two of whom attend public schools in Brooklyn. Bartley proudly claims he is "probably the only editorial writer in New York City who has kids in public schools."

The editor takes his family home every summer to show his daughters what life is like in the Midwest "where people are a little less excitable." He says it was his Norman Rockwell upbringing back in Ames that gave him enough confidence to insinuate his ideas into the minds of people who run big business and big government.

"You grow up with a little elbow room. Things are not constantly buffeted upon you at a tender age," says Bartley. "That kind of upbringing tends to give people a sense of self- confidence."

It's no coincidence, he says, that 40 percent of the nation's corporate chief executives were born in the Midwest, 35 percent of them in small towns.

"It's good for you to spend teen-age summers sweating in cornfields, it's good for you to go to a high school that wins basketball championships, it's good for you to have a dose of old-fashioned ideas about sex," Bartley has written.

Bartley grew up thinking the United States was a wonderful country and, according to several people who grew up with him, Bartley considered himself to be pretty wonderful, too.

"Somewhere along the line, humility escaped Bartley. As someone said about Horace Greeley, he's a self-made man who's in love with his creator," says Tom Emmerson, a high school and college friend, now a professor of journalism at Iowa State. Besides arrogance, Emmerson remembers Bartley's extraordinary intelligence and his "guts."

For example, at Ames High in 1954 the principal decreed that Bermuda shorts could not be worn in school or to Friday night dances. Bartley wrote an editorial in the school paper, Emmerson recalls, "arguing students' rights to wear Bermuda shorts at parties. 'We fail to see what is so esoteric about the knee,' it said."

Both Emmerson and Bartley were called to the principal's office to explain the knee-cap editorial. "One of us was plenty scared," says Emmerson. "The other wasn't. Bart saw the issues clearly.""

While most writers arrive on editorial pages after years of reporting and developing an ideological position, Bartley was a college sophomore when he decided to become an editorial writer. A classmate recalls that when Bartley announced his ambition, a teacher warned him that editorial writing was a crowded field. Bartley replied: "There's always room at the top."

It took an astoundingly short time for Bartley to get to the top. After graduating with a BA in journalism from Iowa State (where he was editor-in- chief of the Iowa State Daily) and an MA in political science from the University of Wisconsin, he joined The Journal in 1962 as a reporter. Two years later, Journal editor Royster invited Bartley to write editorials.

"I just liked the cut of his jib," says Royster. "He wrote well. He was obviously intelligent. We had high hopes for him. We sent sent him out to the Far East and to Vietnam with the instructions that he was to write think pieces. They were impressive, very impressive performances."

Like many people who make their living writing, Bartley is not a particularly persuasive or dramatic talker. He seems, some of his admirers say, deceptively less intelligent in person than in print.

The power of Bartley's pen derives, in large measure, from the power of his pulpit.

The Wall Street Journal, with a circulation of more than 2 million, is the largest circulation daily newspaper in the country. The paper is printed in 14 regional plants and its readers constitute a Who's Who in business and politics.

Journal surveys show that half the paper's subscribers hold "top management positions," 30 percent are chairmen of the board, owners or presidents of companies or chief executive officers. Journal subscribers have an average household income of $68,600, nearly twice the income of subscribers to The Washington Post ($32,776) or The New York Times ($33,664).

Bartley's editorial page, like those of most daily newspapers, is run separately from the news sections of The Journal, so separately that The Journal often seems schizophrenic. Editorials applaud the hardline of Defense Secretary Caspar W. Weinberger while the front page says Weinberger's policy influence is waning. Many Journal reporters consider themselves politically moderate or slightly liberal, while Bartley smilingly accepts a description of himself as a "radically conservative free-market nationalist."

Newspaper editorials, journalistic historians say, are not as influential as they used to be. At a few major newspapers, editorials are dignified, informed and well reasoned; at many others, they are stuffy, noncommittal repositories of stale wisdom. Bartley's page is different.

A Bartley editorial in 1980 condemned President Carter's windfall-profits tax under the headline "Death of Reason." So no one would mistake his point, Bartley framed the editorial with a bold black border.

To excoriate Sen. Edward Kennedy for inconsistencies in his account of the death of Mary Jo Kopechne, Bartley-- in a newspaper that almost never prints photographs--ran four pictures of Chappaquiddick Island on the editorial page.

In a newspaper whose very name means big business, Bartley gleefully denounces corporations (Chrysler, in particular) for feeding at the trough of big government.

Journal editorials sometimes break news and pressure other news organizations, including the news side of The Journal, to deal with subjects they might otherwise ignore.

The most recent example of this is Bartley's crusade to expose the Russians' alleged use of biological weapons. Bartley's pages have carried at least 29 stories on "yellow rain." The barrage of reporting and harangue (yellow rain, Bartley writes, turns "lungs into gushers of blood") pushed the State Department and skeptical news organizations to eikxamine the issue.

"The Journal was a constant irritant. It kept the pressure on the government to investigate the use of biological weapons," says Jim Dobbins, who directed the State Department's investigation of yellow rain.

"Bartley made that issue," says Edwin Guthman, editor of The Philadelphia Inquirer.

"I think Bartley's campaign on yellow rain has been a great journalistic achievement," says Walter Mossberg, who covers the Pentagon for The Journal. The paper's news pages, for the most part, ignored yellow rain. "We probably should have done more."

Until the late 1960s, Bartley couldn't see himself taking over the editorial page of The Journal. He found it "knee-jerk conservative. We had editorials defending cigarettes in the cancer issue, which I thought were a little much," says Bartley.

"The turning point was the student unrest and the general turmoil of the '60s. In particular, the reaction to that by the liberal establishment, even more particularly by the universities, which seemed to sell out all the values they supposedly had been championing. They sold out free speech first. The secretary of defense couldn't speak at Harvard. That symbolized the whole thing."

At about that time Bartley discovered the budding neoconservative movement.

"One of the things that traditionally held me back from conservatism was the lack of an intellectual patina," says Bartley. Then he started reading The Public Interest, a quarterly journal of neoconservatism, and became friends with Irving Kristol, founding editor of The Public Interest and the acknowledged "Don Corleone" of the neocons.

In neoconservatism, Bartley found a scholarly, passionate defense of his American verities: capitalist institutions, the sanctity of law, traditional family values. He also found biting denunciations of the things he felt were tearing America apart: student radicalism, excessive government regulation, knee-jerk environmentalism and the "New Class" of university, government and media intellectuals who doted on the nation's failures while ignoring that "America is a pretty good society."

After his ideological rebirth, Bartley was sent to Washington in 1971 to find out how the federal government worked. He quickly found he didn't like the government or the city.

"Everyone you meet there is absorbed in the same business, often in the same arguments that often don't amount to that much," Bartley says.

Bartley kept to himself at The Journal's Washington bureau. Reporters there joked about Bartley being a loner and a conservative kook. The jokes, however, didn't last long. When a heart attack killed the editorial page editor of The Journal in 1972, the paper was desperate for a replacement.

"When I retired I thought I left things in great hands with Joseph P. Evans," says Royster. "Then Joe up and died, boom. So Warren Phillips (chairman and chief executive of Dow Jones, which publishes the Journal) then was confronted with the problem of what the hell do we do now. A decision was made that Bob Bartley was by far the up-and- coming brightest guy around."

Bartley was only 33, but he was already a committed neoconservative. "He is the world's youngest old fogey," Fred Taylor, executive editor of The Journal, said at the time.

Bartley's first act after taking over was to ask his friend George Will to work for him. Will didn't accept the offer, so Bartley turned to Jude Wanniski, another friend and then a columinist for the National Observer, a now-defunct Dow Jones weekly. Says Wanniski: "Bartley told me, 'Jude, all it takes is arrogance.'"

Together they made the editorial page a neoconservative soapbox. The marriage of The Journal to the neocons suited both. Writers like Kristol, Norman Podhoretz and George Gilder, whose work had been confined to small conservative journals, were given access to The Journal's growing readership in signed articles on the editorial page. In turn, Bartley and his new stable of writers jazeikzed up the old-fashioned capitalism of The Journal's editorial pages.

The marriage was hardly suprising. As Peter Steinful, author of The Neoconservatives, writes: "Neoconservative doctrine is highly congenial to the dominant economic interests in American life. Neoconservatism places few demands upon our major institutions; it asks no grave sacrifices . . . Defending capitalism in the most powerful capitalist nation in the world is not exactly like being an abolitionist in the slaveholding South."

Bartley built an editorial staff of 17, including seven conservative editorial writers who were expected to build "muzzle-velocity" into their writing.

"You really were required to be enthusiastic about the world of ideas. Bartley wanted people who get angry or passionate," says Wanniski. "My standard procedure was to buy The New York Times in the morning, get on my train to New York and by the time I got to work, I was furious about something."

Bartley quickly settled into a routine described by his wife as "too much work." He wakes up at 7 a.m., reads The Journal and The New York Times and takes a subway to work, arriving at about 9:15 a.m. He leaves work about 6 p.m., frequently to attend dinners with Manhattan's neocon crowd or businessmen.

At home in Brooklyn, Bartley plays tennis with his wife once a week. Edith Bartley says her husband, who doesn't read many books because he's too busy reading documents related to arms control or articles in economic journals, spends a great deal of time worrying about the "state of the economy," "national security," and "what the Russians are doing."

It was Bartley's worry about the nagging 1970s problem of stagflation--inflation and limp economic growth--that led him to what was then a little- known theory called supply- side economics. Wanniski brought the theory to Bartley's attention by arguing that the cure for stagflation was a sharp tax cut that would give businessmen money to resuscitate the economy.

Wanniski had befriended two conservative economists, Robert Mundell and Arthur B. Laffer (father of the Laffer Curve), who'd converted him to supply-side. It took years of proselytizing by Wanniski before Bartley converted to the supply-side faith in 1975. Since then he has devoted hundreds of editorials and articles to defending the faith. For the same reasons that Bartley's honor- the-establishment neoconservatism was a hit on the editorial page, supply-side economics found an eager audience among business leaders.

The Journal's supply-side crusade, in the person of associate editorial page editor Wanniski, went beyond mere editorial support. Wanniski became a policy adviser to several Republican political candidates.

"It was to such a point that we felt constrained not to write about Jack Kemp. We felt paralyzed," says Albert R. Hunt, a Journal political reporter. "There was no way to write about Kemp without saying his chief braintruster was Wanniski."

One Journal reporter says Wanniski promised some politicians favorable coverage in the Journal if they would adopt the supply-side faith. Wanniski denies making any such promises. Wanniski says he felt "all right" about giving campaign advice to politicians because he regularly told Bartley what he was doing.

Wanniski resigned from the paper in 1978 after Journal executives noticed him in a train station in Hoboken, N.J., handing out brochures for a Republican Senate candidate. Wanniski blames reporters from The Journal's Washington bureau for forcing him to leave the paper.

"They resented the hell out of me for stomping on their turf," says Wanniski. "They were looking for ways to break my legs all the way along."

The rancor that has erupted at The Journal--especially between Bartley and the Washington bureau--has been extraordinary.

"Bartley thinks we are all kind of left-wing lunatics down here," says Journal Washington reporter James Perry.

The animosity came to a head at a dinner two years ago at the Madison Hotel in Washington. Bureau reporters were angry because they claimed Bartley had been giving them less space on his page for their byline analysis stories. Bartley says he was belligerent because he knew (as did no one else at dinner) that he'd won a Pulitzer Prize. Nearly everyone at dinner had been drinking.

Bartley, according to several reporters at the dinner, said he was not interested in a plurality of views on his page. Instead, he was interested in stories that would not appear "ridiculous" in the eyes of his sources. He further said, according to reporters at the dinner, that the Washington bureau was too close to their liberal sources to be trusted and that he runs his page for like- minded conservatives.

The dinner deteriorated into a yelling match between bureau chief Norman C. Miller and Bartley.

Of the dinner, Bartley says: "My basic thrust was: 'Look, we (editorial writers) are journalists, too. We have our sources, we do our reporting. Sometimes our sources are better than yours.' That's what got them."

Since the dinner, which Bartley says he "didn't handle very well," reporters say they've had better access to the editorial page. Bureau chief Miller was invited to write a regular column. Bartley expanded liberal comment on the page with regular contributions from former State Department spokesman Hodding Carter III and Village Voice columnist Alexander Cockburn.

Although Ronald Reagan has embraced many of the same ideas Bartley has been pushing for years, some of them, most notably supply-side economics, have not fared well.

Tax cuts for corporations and wealthy individuals have not led businessmen to invest in new plants and equipment, as supply-side theory claimed they would. The Commerce Department says businesses plan to invest 2.4 percent less this year than in 1981.

On Bartley's own editorial page, Journal Washington bureau chief Miller wrote in February: "The problem is that too many people don't believe the supply-side theory. Wall Street doesn't believe it, and, most importantly, the Federal Reserve Board doesn't believe it . . . Politically, opinion polls consistently indicate that the public gives high priority to curbing deficits. Sizable majorities say budget balancing is more important than tax cuts . . . "

But some of Bartley's pleas for tougher dealings with the Soviets have become American policy. Journal editorials demanded U.S. trade sanctions to delay Soviet construction of a natural gas pipeline. Despite heavy lobbying from American firms involved in the deal, as well as pressure from several Western European countries, Reagan last month ordered the sanctions.

In his Manhattan office, Bartley doesn't appear particularly excited about his recent victories or losses. News accounts about waning influence of supply-siders or defense hard- liners in the Reagan administration don't seem to concern him.

"This whole thing about what personality is up, what personality is down, is a Washington preoccupation," he says.

The editor has more important things to worry about. As his year-end editorial said last December, "We find ourselves pondering what psychologists call 'denial,' the neurotic refusal to admit reality precisely because it is so threatening."

Bartley claims that through most of the 1960s and 1970s, leaders of the federal government and the mass media suffered from this denial neurosis, infecting millions of American with it. The election of Ronald Reagan, in Bartley's view, marks the beginning of a cure

By dealing "with the grubby realities of today's world," Bartley sees himself as part of that cure.