INFORMED PEOPLE say it: the women's movement, and specifically the Equal Rights Amendment campaign, have been hurt as much by its leaders as its adversaries. Such pundits cite polls showing overwhelming support for the ERA - 80 percent in one poll - and ask how any cause with such popular clout could be in such legislative trouble. Their answer: the women leaders who embraced lesbian rights, who spat at a state capitol policeman, who did not understand how to win political allies, who simply could not be taken seriously. The strenuous efforts resulting in the extension of the ERA time limit would never have been necessary, the argument goes, if the women leaders hadn't botched ERA in the first place.

More than 2,000 of these women leaders came together last weekend at the Washington Hilton for an annual conference of the National Organization for Women. And a lot of the women would turn a lot of people off.

An impressive number of them lost control of their bodies countless calories ago. Others were dressed to the nines - for Halloween. There were women running around looking busy and others sautering around looking tough and they managed in the end to look merely unattractive. There were women who simply will not be taken seriously by uncommitted legislators. But there were many more who must be taken seriously.

There was Dixie L. Johnson of Grand Coulee, Wash., who said she was in her 40s, was for years a banker, and lately has been an artist. Johnson became active in NOW a year ago. "I went to the Washington state conference and I realized all of us were needed. It wasn't just enought to send money in once a year. I went back to Grand Coulee and started a NOW chapter. There are 25 people in it, which, if you've ever been to Grand Coulee, you would recognize is very large."

Johnson was in Washington in the 1950s, playing trombone in the Air Force all-woman band. Then she went west to college. She wanted to be a musician. "I wasn't allowed to audition. I wasn't allowed in the college band because I was a woman." Johnson is friendly, soft-spoken, determined, ERA is terribly important to her, "so young women never have to go through what we had to. We're going to make changes."

And there was Sonia L. Baxter of Murriville, Pa., who was there with her 4-month-old daughter. She came to find out what she could do for ERA. Baxter, who also has a 2-year-old, works as a mother now. Before, she managed a savings and loan in New York City.

And at the center of it all was Eleanor Smeal, the formidable woman who has been president of NOW for the past 18 months, who led it from discord bordering on disarray to accord and triumph. When she took over, NOW had 60,000 members. By the end of this year, she said, it will have 100,000 members and a budget of $2 million. When Smeal took over, ERA was an isolated feminist cause being treated in legislatures as seriously as efforts to ban the bomb. Smeal helped weld the coalition of established political interests that rescued the amendment from oblivion.

NOW's conference this year cost $30,000, more than the entire orgnization spent in its first five years of existence. It resembled a political convention in the way delegates were seated in the ballroom. There was the enthusiasm of a political convention and a discipline that transcended minor factionalism. Smeal runs a tight convention. Told at one point that two delegates who were particularly interested in voting on a resolution were in a workshop, she gave the bad news to their messenger: "You go and find them and tell them to get back in here. They have no business meeting during the plenary session. The plenary session takes precedence over everything else. Go tell them to get right back here. This isn't the U.S. Senate or the House of Representatives. You don't come in here just to vote."

Smeal talks a rough, radical game that involves fundamental restructuring of the American economy. "We are moving daily not only for the ratification of the ERA but for the true equality of men and women," she said in her opening speech. "We have delivered to the right wing a major defeat." She speaks of the "vested interests that profited from underpaying us."

But she also talks practical politics: "The movement is becoming increasingly political. We will be much more involved in elections and we have allied ourselves with other groups, not as a weak sister but as someone who can deliver in our own right. One of our allies in the ERA fight has been labor unions. We are becoming more and more allied."

Smeal repeatedly stressed the role of organized labor in lobbying on behalf of the ERA extension in Congress. Two women labor union leaders who spoke to the conference were greeted with standing ovations. So was Elisa Sanchez, president of the Mexican American Women's National Assocition, who aksed the NOW women to find common ground with Hispanic women.

NOW is still a young movement, making mistakes, but that is learning valuable lessons: e.g., that when you make common cause with organized labor you have made a good match.

Powerful people are paying attention to NOW. Sen. Edward Kennedy (D-Mass.) spoke at the conference, vowing to use his position on the judiciary and human resource committees to better the lot of American women. Joan Mondale, who recently persuaded Senate wives to lobby their husbands on behalf of ERA, spoke to NOW: "Winning the equal rights extension was a superb victory for the women and men of American and I'm here to say thank you to the National Organization for Women."

Smeal spoke of those who opposed extending the ERA time limit, offering the last ditch argument that it had never been done before. "When they said you are changing the rules of the game, we said, 'What game?' 'This is life.'"

It's life and it has to do with women surviving and getting their fair share of the economic pie. Smeal and others acknowledge they made mistakes. They depended on themselves and eschewed the traditional and emerging power bases which could have helped them. Maybe they didn't realize what they had to offer in return.

They do now. For the time being, at least, the feminist movement knows it must be taken seriously. It's a force now because it has learned to court labor unions, civil rights organizations, Common Cause, church and senior citizen groups, local politicians, U.S. senators and their wives, and the president and vice president of the United States and their wives.

It has learned, in other words, to play the game of politics.