The Obama administration overstepped its legal authority — and injected politics into what should have been a scientific decision — when it ordered the FDA to limit the availability of a common morning-after contraceptive without prescription to girls and women 17 and older. The FDA had evaluated the drug and determined that it was safe for females of all ages and should be available to all. That’s why U.S. District Court Judge Edward R. Korman last month overruled the administration’s decision and ordered that the drug be made available without prescription to females regardless of age.

The judge was right. And the Justice Department’s decision, announced Wednesday, to appeal that ruling is a mistake. Not only does it compound the administration’s first legal misstep, but it is a disappointing and disturbing attempt to limit contraceptive rights without any scientific justification for doing so.

As the judge noted in his opinion, scientists had found the drug — Plan B One-Step — safe and effective for adolescent females. He dismissed Secretary of Health and Human Services Kathleen Sebelius’ stated objection that the FDA studies failed to consider whether the youngest girls might not be able to understand the labels, and her suggestion that girls as young as 11 (only a small percentage of whom are able to become pregnant) might lack the cognitive sophistication to use the drug properly.

The judge found that Sebelius had overruled the FDA in an area Congress has specifically entrusted to the FDA. He bluntly scoffed at the secretary’s reasoning: “This case is not about the potential misuse of Plan B by 11-year-olds. These emergency contraceptives would be among the safest drugs sold over-the-counter,” he wrote.

Who would have expected access to contraception to be curtailed by an administration that has generally been so supportive?

The real issue underlying what should be a simple case about whether this drug is safe (and who should decide whether it is) is a more complicated and emotional one that has to do with parents and children and when young people should or shouldn’t begin having sex. But no matter where you come out on that question, the reality is that banning the morning-after pill will not deter girls from having sex. All it will do is force some of them into unwanted pregnancies.