Mr. Obama had expressed personal concern about making the drug more broadly available last year and offered support to Kathleen Sebelius, his secretary of health and human services, when she blocked a decision by the F.D.A. that would have cleared the way for nonprescription distribution to all girls and women regardless of age. He said that as the father of two young girls, the idea of making the drug available to them without a prescription made him uncomfortable.

But a federal judge angrily accused the administration of blocking the drug because of politics, not science, and ordered Ms. Sebelius to reverse her decision. Last week the Court of Appeals for the Second Circuit in New York City partially refused the Justice Department’s request for a delay in the judge’s order while the government appealed.

In its letter to the court, the Justice Department outlined the procedural steps that the F.D.A. plans to take. It said the maker of Plan B One-Step, Teva Pharmaceuticals, has been asked to “promptly” file an application asking for no age or sales restrictions, and that the “F.D.A. will approve it without delay.”

Once that is done, the F.D.A. expects makers of generic versions of Plan B One-Step — the most popular of those is Next Choice One Dose — to ask for a similar arrangement. The F.D.A. will evaluate those requests, based on whether it decides to give Plan B One-Step any type of market exclusivity, but most likely generic pills will also eventually be available without restrictions.

The Justice Department said it would not remove restrictions from two-pill emergency contraceptives because it is concerned that young girls might not be able to adequately understand how to take two separate doses. But two-pill versions are a diminishing fraction of the market.

The fight to make emergency contraceptives universally available without a prescription is more than a decade old. Plan B, the trade name for the morning-after pill, was approved in 1999 as a prescription-only product. In 2001 the Center for Reproductive Rights filed a citizens petition for it to be made available over the counter or without a prescription.

By December 2011, after years of pressure from women’s reproductive rights groups and the companies selling the drug, the F.D.A. was poised to lift all age restrictions. By then the F.D.A. also said it had determined that the drug was safe. But in an unprecedented move Ms. Sebelius overruled the agency. She said at the time that she had based her decision on science because she said the manufacturer had failed to study whether the drug was safe for girls as young as 11, about 10 percent of whom are physically able to bear children.