“If a patient comes into the emergency room with a medical emergency jeopardizing the patient’s life or health, hospitals must provide the treatment necessary to stabilize that patient,” Attorney General Merrick Garland said. “This includes abortion when that is the necessary treatment.”

Idaho has a ban set to take effect later this month. The law has exceptions allowing doctors to perform abortions to save the life of a pregnant woman or in cases of rape or incest that have been reported to law enforcement. It explicitly excludes cases in which a physician believes that a woman will harm herself if the abortion isn’t performed.

Penalties for providers who violate Idaho’s law range from two to five years in prison.

Mr. Garland had vowed to take legal action to protect access to abortion after the Supreme Court’s ruling left a patchwork of state laws, and abortion-rights groups had been urging the Biden administration to look for all available legal avenues to preserve at least some availability of the procedure in states seeking to eliminate it.

Idaho Gov. Brad Little, a Republican, said in a statement that the Biden administration was “overreaching” after the Supreme Court left the issue of regulating abortion to the states.

“I will continue to work with [Idaho] Attorney General Lawrence Wasden to vigorously uphold state sovereignty and defend Idaho’s laws in the face of federal meddling,” Mr. Little said.

Idaho is one of 13 states that passed so-called trigger laws in recent years that were designed to take effect immediately or quickly after a decision overturning Roe v. Wade, the 1973 decision that established a constitutional right to an abortion. In the June decision Dobbs v. Jackson Women’s Health Organization, a majority of the court said there was no provision in the Constitution that implicitly protected the right to an abortion, returning the issue to the states.

Idaho’s law is similar to the dozen or so other laws that have been going into effect in states around the country, all of which provide exceptions for the life of the mother and some of which also allow abortion in the case of rape, incest or potential severe health issues for the mother or fetus.

Abortion providers have challenged a number of these laws in state courts, in part arguing that these exceptions are vaguely worded and could put them at legal risk in providing care for miscarriages and life-threatening pregnancy complications. Planned Parenthood and an Idaho abortion provider filed a lawsuit against the trigger law in the Idaho Supreme Court days after the Supreme Court’s decision in June. They claim the law violates protections for privacy and equal protection in the state constitution and that its language is too vague for providers to make determinations about what care they can legally provide.

Tuesday’s lawsuit is the first of its kind since the department formed a task force led by Associate Attorney General Vanita Gupta to evaluate state laws that hinder women’s ability to seek abortions in other states where the procedure remains legal or that ban federally approved medication that terminates a pregnancy.