Two dozen Republican attorneys general are warning the White House of impending legal action if a proposed coronavirus vaccine requirement for as many as 100 million Americans goes into effect.

The letter sent Thursday is the latest in GOP opposition to sweeping new federal vaccine requirements for private-sector employees, health care workers and federal contractors announced by President Joe Biden earlier this month. The requirement, to be enacted through a rule from the Occupational Safety and Health Administration, is part of an all-out effort to curb the surging COVID-19 delta variant.

The prosecutors, led by Attorney General Alan Wilson of South Carolina, called Biden’s plan “disastrous and counterproductive.” They wrote: “If your Administration does not alter its course, the undersigned state Attorneys General will seek every available legal option to hold you accountable and uphold the rule of law.”

In addition to South Carolina, the letter was signed by attorneys general in Alabama, Alaska, Arizona, Arkansas, Florida, Georgia, Indiana, Kansas, Kentucky, Louisiana, Mississippi, Missouri, Montana, Nebraska, New Hampshire, North Dakota, Ohio, Oklahoma, South Dakota, Texas, Utah, West Virginia, and Wyoming.