President Biden declared on Friday that he believes that the Equal Rights Amendment has met the requirements of ratification and therefore is now part of the Constitution, but he declined to order the government to finalize the process by officially publishing it.

“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, guaranteeing all Americans equal rights and protections under the law regardless of their sex,” Mr. Biden said in a statement.

Under the Constitution, however, the president has no direct role in approving amendments and his statement has no legal force by itself. The archivist of the United States, a Biden appointee, has refused to formally publish the amendment on the grounds that it has not met the requirements to become part of the Constitution.

Aides said that Mr. Biden was not ordering the archivist, Colleen Shogan, to reverse her position and publish the amendment, as advocates have urged him to do. Asked for comment on Friday, the archivist’s office referred back to previous statements refusing to publish the amendment, indicating that she would not change her stance.

Even so, advocates maintained that Mr. Biden’s imprimatur gives the amendment additional credibility for any future court battle over whether it actually has the force of law. In effect, Mr. Biden and his allies are daring opponents to go to court to argue that women do not have equal rights.