WASHINGTON, United States (AFP) — Outgoing President Joe Biden said Friday that the Equal Rights Amendment (ERA), designed to ensure equality before the law regardless of one’s sex, is already part of the US constitution — a view disputed by political opponents as well as the National Archives.

“In keeping with my oath and duty to Constitution and country, I affirm what I believe and what three-fourths of the states have ratified: the 28th Amendment is the law of the land,” Biden said in a statement.

While Biden’s proclamation carries no legal weight, it is seen as a defiant gesture just three days before he cedes power to Republican Donald Trump, whose first-term Justice Department had suggested the amendment was a dead letter.

The US Congress adopted the ERA in 1972 as a measure to give constitutional backing to demands for equal treatment of men and women.

For such an amendment to become US law requires ratification by three-quarters of the states, or 38 of the 50.

Conservative groups fiercely opposed the amendment, arguing that it would open the door to unisex toilets, same-sex marriage and conscription of women into the military, and the ratification process moved slowly.