The National Organization for Women's boycott of vacations and conventions in the 15 states that have not ratified the Equal Rights Amendment is beginning to make itself felt. In the past week, two of the 15, Missouri and Nevada, have filed suit for an end to the boycotts.

The two states charge the boycott violates antitrust laws. But as far as NOW is concerned, the lawsuits are a welcome sight.

"Really, what these states are saying is that the boycott's been effective," said Eleanor Smeal, president of NOW.

Smeal called the suits "attack against freedom of speech and political expression" that are without legal merit.

"We're trying to have the community that supports ERA express itself in different ways, some of them economic ways," she said. "These are states that are suing us, not individuals. People in those states support us. The attorneys general are only listening to one portion of the community, and the vested interests are that portion."

According to NOW, more than 120 organizations support the boycott, among them the United Auto Workers, the Communications Workers of America, and the American Federation of State, County, and Municipal Employes. A valid suit would have to be directed at them as well as at NOW, he said.

Smeal said the boycott has routed "several hundred million dolars" of conventions and vacations away from the 15 states. Recently, she said, the 14,000-member American Nurses' Association canceled reservations it had made in Kansas City for its yearly convention because of the ERA boycott.

Nevada Attorney General Robert List, who filed sued last Friday against NOW, said groups that have canceled conventions in Las Vegas because of the boycott include the American Home Economics Association, the National Legal Aid and Defenders Association, the National Clients Council, and the Speech Communications Association.

"The ultimate goal of this boycott is to coerce businessmen, employes, and other citizens of Nevada, who are dependent on tourism and the movement of people and money into the state for their livelihoods, to put pressure on the state legislature to ratify the amendment," List said.

Smeal would almost certainly agree. She said the boycott is an American political tool as old as the Boston Tea Party. "We think the boycott is part of the normal political process, employed by political groups, civil rights groups labor unions . . . particularly in the furtherance of human rights," she said.

The proposed Equal Rights Amendment to the Constitution has been approved in 35 states. It must be ratified by three more by March 22, 1979, in order to become the 27th amendment.

Smeal noted that while many Americans think of ERA as a symbolic issue, practical matters such as a woman's right to sue in court on the vasis of sex discrimination in employment hinge on the fate of the measure.

"What is now at stake is equality under the law for females in this century," she said.