THE REPUBLICAN WOMAN'S Task Force has decided to send a delegation to the Republican National Convention in Detroit despite growing conviction that a Reagon-dominated convention will succeed in taking ERA out of the Republican platform.If that happens, Republican feminists say they are going to have a tough time deciding whom to support.

"I think a lot of individual decisions are going to be made at the time of the convention," says Pam Curtis, vice-chair of the task force, which was formed to support ERA. "I think our chances of keeping it in the platform are going to be very dim if Ronald Reagan decides he wants it out.

"There are those people who are going to support Reagan because he is the Republican nominee and the party comes first; there are those people who will support him because they want a future within the party structure or a future within a Republican administration. And there are those people who are going to bite the bullet as feminists and support the candidate who is perfect on the issues, which is John Anderson," says Curtis.

She believes that Reagan could get substantial support among moderate Republican women if he retains the ERA plank, or signals his delegates that he does not want a floor fight to take it out. But Reagon has made it clear he is against the ERA and, so far, he has maintained he wants a running mate who agrees with him on the issues.

Republican feminists take pride in pointing out that ERA has been in the party platform since 1940 -- four years before it became part of the Democratic Party's platform. But it was almost removed from the GOP platform during the 1976 convention, even though it had the firm backing of President Ford and his wife.

Reagan's position on the ERA has little to do with how state legislatures will be voting on it during the coming year. But Republican feminists say handling his of the issue between now and the convention will signal whether "he's a little more practical politician than rigid ideologue," as one task force member put it.

"If he chooses to send a signal that the party is going to reverse a historic trend, that will be truly upsetting," she said. "It will be putting moderates and women into a real tailspin as to what they should do . . . If he wants to keep it in, it would be in his interest to send a back channel signal soon before the visibility of the issue is raised.

"Republican women are in two groups at this point," she said. "There are those women who feel that Ronald Reagan has been pretty clear that he is unable and unwilling to support ERA and hence they see no point in being involved with him. And on the other hand, there are the women who feel we don't know him well enough from newspaper stories, and that he may be more pragmatic than he has been given credit for on the East Coast -- and that the worst thing we could do is to assume the worst and simply refuse to try to work with him and with his people."

Leaders of various Republican women's organizations in the Washington area have started meeting to discuss what to do, according to members of the task force. "I think there's a lot of feeling among a number of Republican women that they would like to see some signal from Reagan, some reason why they might be able to support him, such as a moderate as his running mate," said a task force member.

"Ronald Reagan doesn't need to take ERA out to keep the conservative and right-wing vote," she said. "He needs to leave ERA in as a message to people who are trying to decide whether to stay home or to hold their nose and vote for Ronald Reagan."

"He has been so insistent on a running mate being ideologically pure that I can't imagine the platform being impure," says task force member Betsy Griffith. "There are going to be so many Reagan delegates there that I'm not sure where we'd get the body of moderates to lead the fight. Having analysed all of this, the task force has decided we will go to Detroit one more time and go down in flames if necessary. Another thing we are going to do is poll the delegates. That's how we found out last time that even among the Reagan delegates there were some who supported us on these issues."

Bobbie Greene Kilberg, who worked in the Ford and Nixon administration, says Reagan's vice president choice is "crucial" to her.

"I think it is useless and unrealistic for a Republican feminist to expect to find a change in Reagan's position on ERA and abortion. It's obvious that's not going to happen . . . But I think now they ought to concentrate on a lot of other issues that impact on women -- displaced homemakers, pension reform, day care, the marriage tax."

She says the selection of former ambassador to Great Britain Anne Armstrong as a running mate "would be a very smart move on their part," with appeal to moderates and feminists. "A lot of Republican women feel very strongly that at least through the convention they should try to influence the platform and the selection of the vice presidential nominee, and then depending on what happens at the convention, they will decide what to do in the fall."

"I'm a feminist. But I'm also a consumer and wage earner," says Kilberg, "and to me the decision as to whom to support for the presidency is going to be broader than equal rights and abortion. I think the country is in desperate trouble, and I want to make my decision on a much broader basis.

"I think it's very important this year that people not make their presidential choice based on one-issue politics. I just don't think we can afford it," she says.

But to her and other Republican feminists there is, nevertheless, at least one single issue. "I'd be flabbergasted," says Kilberg, "if any of the Republican friends I have would consider voting for Jimmy Carter."