WASHINGTON — The Supreme Court weighed moral theology and parsed insurance terminology on Wednesday in an extended and animated argument that seemed to leave the justices sharply divided over what the government may do to require employers to provide free insurance coverage for contraception to female workers.

A 4-to-4 tie appeared to be a real possibility, which would automatically affirm the four appeals court decisions under review.

All four ruled that religious groups seeking to opt out of the requirement that they pay for the coverage must sign forms and provide information that would shift the cost to insurance companies and the government. A tie vote in the Supreme Court would not set a national precedent, and religious groups in different parts of the country would have conflicting obligations if they object to covering contraception.

Other appeals courts have also agreed that the accommodation offered to religious groups is lawful. But the United States Court of Appeals for the Eighth Circuit, which hears cases from federal courts in Arkansas, Iowa, Minnesota, Missouri, Nebraska, North Dakota and South Dakota, ruled that it violated the Religious Freedom Restoration Act of 1993.