Cleta Deatherage, a highly regarded 31-year-old Oklahoma state representative, is hopping mad.

She has been working for the Equal Rights Amendment in the unfriendly vineyards of Oklahoma politics since her junior year in college. She has given countless speeches for the ERA, raised money for it and coordinated a statewide ERA coalition.

But now, Deatherage says, she is being accused of "not really being a feminist" by ERA supporters. She says she has been lectured to by Eleanor Smeal, president of the National Organization for Women, and been made the subject of a NOW "Yellow Alert" sent around the country.

Some disgruntled ERA supporters have attached notes to her morning newspaper saying: "Want to talk about a dead issue: Your political future," she claims. Others have sent her telegrams phoned from a NOW office in Norman, Okla., which say "Your goose is cooked."

Others have threatened to try to defeat her in the next election.

"Somehow they think we didn't do enough," she complains. "It's really hard to take when you've been working on this as long as I have."

Deatherage--perhaps unfairly--blames her problems on NOW, which has mounted an intense, well-financed last-ditch national campaign to win ratification of the ERA in three more states before the June 30 deadline. This would bring the total to the required two-thirds majority, with the amendment's proponents viewing Illinois, Florida, Oklahoma and North Carolina as their best prospects.

"They're crazy," Deatherage says angrily. "They cannot decide whether they want to be on the fringe or part of the political leadership and they don't understand you can't have it both ways."

Deatherage, first elected with the help of ERA supporters in 1976, has chosen to be an insider, and has risen rapidly in the legislative hierarchy. She is chairman of the House appropriations committee, an ally of the leadership and a member of the national Democratic presidential delegate selection commission.

In the latter role, she opposed making two-thirds of the Democrats in Congress delegates to the party's national convention because not enough are women.

Ruth Adams, NOW's Oklahoma coordinator, categorically denies that NOW has been involved in any effort to unseat or harass Deatherage, whom she calls "the most influential woman state legislator in the country."

She says that the only thing NOW has done was to list Deatherage on an information bulletin, called the Yellow Alert, "to let her know that women all over the country are looking to her for leadership."

The women who sent telegrams and other messages to Deatherage were unhappy constituents who acted on their own, she says. "The fact is that the women of this state felt like she could have used her position to better advantage."

Twyla Mason Gray, a state representative, and Junetta Davis, vice chairwoman of the Oklahoma Women's Political Caucus, confirm this account. "She is trying to make NOW a scapegoat," says Gray. "I think it's unfair."

Davis says she and other women sent Deatherage telegrams because they were bitter that she didn't fight to keep the ERA from being bottled up in a House rules committee of which she is a member. NOW, she says, had nothing to do with the telegrams.

"Nobody is out to get her," says Davis, a journalism professor at the University of Oklahoma. "We just want her to answer some questions. I am very disappointed in her."

Deatherage isn't the only ERA supporter in Oklahoma with bad feelings about NOW. The chief sponsor of the ERA in the Oklahoma House, Speaker Dan Draper, says he was picketed by NOW members and sent "boxes of vicious letters" from around the country. State Democratic Party chairman Obera Bergdall, another longtime ERA supporter, says she received telephone calls at 2 a.m. asking, "What are you doing about ERA?"

The problems apparently centered on ERA strategy. Before the legislative session opened in January, a coalition of ERA supporters, including Adams representing NOW, agreed that they would abide by a strategic decision made by Draper and Marvin York, the Senate president pro tempore.

With the agreement of the ERA coalition, Draper and York decided to bring the amendment up in the state Senate in the early weeks of the session, and not force a vote in the House unless the ERA had won Senate approval.

Draper and York had agreed to lead the ERA fight at considerable political risk, Deatherage says. "I thought having them out front was a big plus. I've been working for years to get men to feel it was their issue."

As the session opened, NOW broke with the strategy. It insisted on calling its own press conferences, holding its own rallies and going door-to-door in the disticts of ERA supporters and opponents.

"If you call the vote for the first part of the session that doesn't give you enough time to build support," Smeal says. "We're in the process of trying to save another generation of women, and all they wanted to do was vote on ERA and move on to other things."

After an intense lobbying effort, the ERA narrowly failed in the Oklahoma Senate. NOW then pressed for a House vote. Deatherage and others resisted this because it would mean abandoning pledges made to York and Draper.