The U.S. Supreme Court’s conservative majority appeared deeply skeptical Friday that the Biden Administration’s vaccine-or-test mandate for large employers was legally authorized, but seemed more inclined to support the vaccine requirement for health care workers in Medicaid and Medicare funded facilities.

The justices heard more than three hours of arguments on the two federal agency rules, but it was clear that a chasm existed between the court’s conservative and liberal wings over whether the Occupational Safety and Health Administration had statutory authority to issue the “emergency temporary standard” for employers with 100 or more employees. The standard requires employers to give their employees a choice: To vaccinate or to test weekly and wear masks in the workplace.