The Equal Rights Amendment
Not all constitutional amendments that are supported by a 2/3 majority in each house of Congress actually become part of the Constitution. The most visible recent example of an amendment that failed to be ratified was the Equal Rights Amendment (ERA). Spurred on by the women's movement of the 1960s and early 1970s, the ERA was designed to give full political and legal equality to women, much as the Fourteenth Amendment gave political and legal equality to former slaves.
The principal provision of the ERA stated:
"Equality of rights under the law shall not be denied or abridged by the United States or by any State on account of sex."
Congress proposed this Amendment in 1972 and it established a seven-year deadline for the amendment's passage. Several states ratified the amendment very quickly. However, by the end of the seven years, the amendment had not been ratified by enough states, and Congress extended the deadline to 1982. It still was not long enough. When the deadline passed, the ERA was still three states short of the 38 states needed for ratification.
Although the ERA failed to attract enough support for ratification, in the past three decades the Supreme Court has interpreted the "equal protection" clause of the Fourteenth Amendment in such a way as to grant women many, but not all, of the rights they would have achieved had the ERA been adopted.