In the new American politics, the sure winners are not candidates but consultants, the people who give advice, take polls, made TV commercials and collect their substantial fees whether their candidate is victorious or not.

A sure thing draws a crowd. So every electoral season more consultants materialize to compete for the available work. This year, it's Penn & Schoen, who have materialized. They intend to materialize into a big business.

Penn & Schoen are "kid pollsters," as one of their competitors described them. Mark J. Penn and Douglas E. Schoen are both 26. They have been working on polls together for nearly five years, but have only been in business formally as Penn & Schoen Associates for a year. In time, perhaps, they will displace Patrick Caddell, the president's public-opinion counselor, as the reigning "whiz kid" of American pollsters.

According to an expert estimate, candidates of all kinds will spend as much as $20 million during 1980 on as many as 2,000 polls. This is a generous pie from which to cut slices, as Penn & Schoen have already discovered.

They have already done lucrative polling work for the new major of Philadelphia, William J. Green, Mayor Ed Koch of New York, Gov. Hugh L. Carey of New York, Gov. Ella T. Grasso of Connecticut and Luis Herrera, the president of Venezuela, among others. Most of their work has come to them through David Garth, one of the handful of political consultants who can regularly turn away business and work only for candidates of his choice.

This year Garth is hoping to look after the presidential candidacy of Rep. John B. Anderson (R-Ill.), and Penn & Schoen acknowledge that they'd like to be involved, too. According to others in the business, Penn & Schoen have already done some polling for Anderson. They denied this at first, then said "no comment."

They also had "no comment" on well-informed reports that they tested the water late last year for Gen. Alexander M. Haig. One sources said their poll found that Americans thought Haig might be president some day, but not this year. The general decided not to run.

Discretion, Penn & Schoen have decided, is a good business practice. They have decided never to discuss their political clients publicly unless their relationship is already known. They have also decided, they say, never to leak the results of their polls, also to help build a reputation for total discretion.

The other point that both men want people to understand is their speed in conducting a poll. They are out to be the fastest pollsters around. The Kennedy campaign called them some weeks ago on a Saturday to ask for a quick telephone poll. The poll was completed and its results thoroughly tabulated and analyzed by Monday morning, Schoen said in an interview.

Schoen is the smoother operator of these partners. Friends from Harvard, Oxford University (where he earned a PhD in two years) and New York describe him as a great promoter, particularly of himself.

Schoen grew up comfortably on the East Side of Manhattan, the son of a corporation lawyer. He has talked of running for Congress, and he has already published two books, his PhD thesis on the British politician Enoch Powell, and a flattering biography of Sen. Daniel Patrick Moynihan (D-N.Y.).

"Out of sheer determination," one friend recalled, Schoen transformed himself after college from an overweight and rather slovenly undergraduate into a trim, well-dressed man about two. "He is one of the most ambitious people I have ever met," this friend said.

Penn seems less polished and more wrapped up in the nuts and bolts of polling. He is a big, bulging man with a quick smile. He grew up in Queens, the son of a kosher poulterer who died when Penn was 12. He did his first polling at the Horace Mann School, a private school in Riverdale, the Bronx, discovering how many students smoked marijuana, and how the school faculty felt about race relations.

That faculty survey, based on a CBS Poll included a question asking respondents to rank various civil rights leaders as to their militancy. Ten percent of the Horace Mann faculty thought a civil rights leader named Perry Wolf was "too militant," Penn's poll found. Perry Wolf was a name invented for use in the poll, to see how respondents would handle a mythical figure.

At Harvard Penn was the pollster for the student paper, The Crimson, where Schoen was an editor. The two began to collaborate as undergraduates. Their first commercial undertaking was a 1974 study of 8,000 voting districts in metropolitan New York to try to identify the characteristics of swing districts as a guide to get-out-the-vote efforts by the state Democratic Party. "Our analysis was used for years," Penn said in an interview here.

The New York State Democratic Party also commissioned their first poll, a 1975 survey of New York voters' attitudes toward Sen. Henry M. Jackson (D-Wash.) as a possible presidential candidate. Penn recalls that they discussed whether it would be worthwhile to evaluate Jimmy Carter at the same time, but they decided not to.

With tutoring from Garth, Penn and Schoen became the pollsters for Ed Koch in 1976 and 1977. "That's where we developed a lot of the skills and techniques that we're using," Penn said.

Specifically, they worked on speedy results and continual "tracking," to keep on top of any shifts in public attitudes toward Koch. They set up their own polling operation, rather than use an independent interviewing organization, which many pollsters do. The Washington Post Poll, for example, is drawn up by the Post, but the interviews are conducted by a New York interviewing firm.

Penn & Schoen handled the computer processing, too. Now they own their own computer.

For 10 days between the first mayoral primary in 1977 and a second runoff, they did daily updates for Koch. In an article in the New York Times after the general election in November, they admitted that Koch was steadily losing support to his opponent, Mario Cuomo, in the last days of the campaign, a fact that could have hurt more if it had been known publicly, they said. Koch beat Cuomo by 8 percent.

Even with this experience Penn & Schoen remained semi-pro pollsters. Both were in law school; their "office" was a cluttered room in Morningside Heights, which was Penn's home while he studied at Columbia. It was in that messy room that Penn first talked with political aides to Gov. Carey, who eventually used the two men as his pollsters in the 1978 election campaign.

In 1978 Garth took Penn to Venezuela, where he designed a polling system for a presidential candidate that apparently worked. In America Penn & Schoen use only telephone polls, but this was impossible in Venezuela, so Penn organized a door-to-door survey. Last fall in Philadelphia the firm set up a local polling operation so Green could have the benefit of saturation surveys.

The need for constant surveying is a hallmark of the Penn & Schoen sales pitch, though in separate interviews the two partners contradicted each other on the question of why it is desirable. Schoen said, "It is our asity in the electorate and late shift of opinion in campaign that only contant polling can detect.

Penn said later, "It's not that there's more volatility, it's that there's a lot more polling, and people are picking up the volatility." Penn said he thought voters' opinions are subject to wild shifts "on any issue that gets a tremendous amount of attention" from the news media.

Whatever the explanation, Penn & Schoen -- and a lot of politicians agree that unexpected shifts in opinion are a kind of political devil that smart candidates will seek to disarm.

They have sold the idea this year, for example, to Joseph I. Lieberman, majority leader of the Connecticut state Senate, who is running for the House seat being vacated by Robert N. Giaimo (D-Conn.). For $9,000, Penn & Schoen will conduct a detailed "baseline" poll in that district around New Haven, and the firm will then help the Lieberman campaign conduct its own follow-up "tracking" polls and process the results for about $1,000 each time. For more extensive services in Philadelphia last year, Mayor Green paid the firm $95,750.

Politics is in a state of flux, but Penn & Schoen ar confident about the future of the polling business. "The prospects are right," Penn said.