Why did the equal rights amendment fail to pass?

The founder of National Women's Party, Alice Paul first presented the Equal Rights Amendment to Congress in 1923. She would work for the way of the ERA until her death in 1977. "Equality of rights under the law shall not be abridged by the United States or by any State on account of sex."  This suggested banning discrimination based on sex. On March 22, 1972, it was passed by the Congress then the E.R.A. was sent to the states for ratification but it was cut down by three states short of the 38 required for approval by a June 30, 1982 deadline. 

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