The Greens told the justices in their brief that some drugs and devices that can prevent embryos from implanting in the womb are tantamount to abortion and that providing insurance coverage for those forms of contraception would make the company and its owners complicit in the practice. They said they had no objection to 16 other forms of contraception approved by the Food and Drug Administration, including condoms, diaphragms, sponges, several kinds of birth control pills and sterilization surgery.

But Hobby Lobby’s failure to offer comprehensive coverage could, it said, subject it to federal fines of $1.3 million a day. Dropping insurance coverage for its employees, it added, would be disruptive and unfair and lead to fines of $26 million a year.

Mr. Verrilli countered that requiring insurance plans to include comprehensive coverage for contraception was justified by the government’s interest in “the promotion of public health” and in ensuring that “women have equal access to health care services.” Doctors rather than employers should decide which form of contraception is best, he added.

The administration has excluded many religious organizations from the law’s requirements; it has grandfathered some insurance plans that had not previously offered the coverage; and, under the health care law, small employers need not offer health coverage at all. In June, a federal judge in Tampa, Fla., estimated that a third of Americans are not subject to the requirement that their employers provide coverage for contraceptives.

But the administration drew a line at larger, for-profit, secular corporations.

“Congress has granted religious organizations alone the latitude to discriminate on the basis of religion in setting the terms and conditions of employment, including compensation,” the Justice Department told the 10th Circuit appeals court, in Denver.

“No court has ever found a for-profit company to be a religious organization for purposes of federal law,” the brief went on. “To the contrary, courts have emphasized that an entity’s for-profit status is an objective criterion that allows courts to distinguish a secular company from a potentially religious organization, without conducting an intrusive inquiry into the entity’s religious beliefs.”

The appeals court disagreed, ruling that Hobby Lobby is a “person” for purposes of the relevant federal law, the Religious Freedom Restoration Act of 1993.