Colorado is set to defend its anti-discrimination law before the nation’s highest court, filing a brief on Friday that pushes back against a Christian website designer’s refusal to provide her services for same-sex weddings.

The U.S. Supreme Court in its upcoming term will hear the case of 303 Creative LLC v. Elenis, which asks whether Colorado law can compel Lorie Smith to create wedding websites regardless of sexual orientation, or if she may turn down requests based on her belief that marriage is only between men and women.

On Friday, the Colorado Attorney General’s Office submitted its response to Smith’s opening brief, asserting that the Colorado Anti-Discrimination Act does not impermissibly infringe on Smith’s speech. Rather, it requires businesses providing goods and services to the public to refrain from turning away customers because of who they are.

“A book is expressive; selling a book to the public is not. Designing a home is expressive; selling that design service to the public is not,” the office wrote. “By regulating routine commercial conduct, the Act addresses what a business does and not what it says.”

In a virtual press conference earlier on Friday, Attorney General Phil Weiser warned the conservative-majority court’s decision could conceivably imperil anti-discrimination protections in businesses serving the public based on other characteristics, such as race or religion, and not simply sexual orientation.

“The free speech claim advanced here, we think, is dangerous, and one that, if granted, could open up a whole range of loopholes to anti-discrimination law and public accommodations requirements,” Weiser said.

The government repeatedly appealed to the “history” and “tradition” of ensuring equal access to goods and services. In recent decisions, the Supreme Court’s majority has looked to early American history to, for instance, invalidate constitutional protections for abortion and raise the threshold for gun safety regulations. Colorado’s defense of its anti-discrimination law potentially seeks to head off any doubts from the conservative justices about the legitimacy of the law’s protections.

“At the Founding, American common law required businesses open to the public to provide their services to all customers,” Weiser’s office argued. “These statutes have covered different accommodations and different protected classes over time. But the common thread is the state’s authority to require a business that sells its goods or services to the public to serve all comers.”

To Smith, the issue is whether government may use public-accommodation laws to “compel artists to speak or stay silent when they enter the marketplace.”

To answer “yes,” Smith told the Supreme Court, would be “unprecedented.”

She argued that Colorado’s law, by forbidding discrimination on the basis of sexual orientation, necessarily forces her to adopt a point of view on marriage that runs contrary to her religious beliefs.

“Smith lives in a state where government officials and private parties have relentlessly plied the State’s public accommodation law …  to compel speech the government favors and silence speech the government dislikes,” she told the court.

The earliest version of the anti-discrimination law, known as CADA for short, dates to 1885, less than a decade after Colorado statehood. The legislature amended it in 2008 to prevent businesses open to the public from denying goods or services based on sexual orientation.

The question of whether CADA violates the free speech rights of those who refuse to serve LGBTQ customers previously reached the Supreme Court in 2017, with the case of Masterpiece Cakeshop v. Colorado Civil Rights Commission. The court decided the appeal on a narrow issue specific to the lawsuit, leaving the constitutional issue for the future — in what would become the 303 Creative case.

Even though Smith has not yet refused anyone service, nor has the state taken enforcement action against her, the case has already risen through the federal courts in a precedent-setting fashion. By a 2-1 decision last summer, the U.S. Court of Appeals for the 10th Circuit found CADA did compel Smith to create websites for same-sex and opposite-sex couples alike, but that the law did not violate the First Amendment because it was the least-restrictive means of advancing an important governmental interest.

“As Colorado makes clear, CADA is intended to remedy a long and invidious history of discrimination based on sexual orientation,” wrote Senior Judge Mary Beck Briscoe for the majority.

Chief Judge Timothy M. Tymkovich wrote a forceful dissent, quoting novelist George Orwell and warning of a “slippery slope” toward authoritarianism that would result from stifling the speech of minorities.

“(T)he majority takes the remarkable — and novel — stance that the government may force Ms. Smith to produce messages that violate her conscience. In doing so, the majority concludes not only that Colorado has a compelling interest in forcing Ms. Smith to speak a government-approved message against her religious beliefs, but also that its public-accommodation law is the least restrictive means of accomplishing this goal,” Tymkovich wrote.

In February, the Supreme Court agreed to hear Smith’s appeal of the 10th Circuit’s decision. Smith, in her opening brief, argued CADA forces “artists” to convey “government-sanctioned messages” in their work, even if those run contrary to their religious beliefs.

The case has drawn heavy interest from conservative and religious groups supporting Smith.

The Court in recent years has issued multiple landmark decisions cementing the prominence of religion in the public sphere. This past term, the court’s majority held Maine must also subsidize private religious education if it continues to subsidize nonsectarian schooling for rural students, and a Washington school district could not prohibit a public school football coach from leading Christian prayers after games.

Colorado’s solicitor general, Eric Olson, will argue before the Supreme Court on behalf of Colorado. Smith is represented by the Alliance Defending Freedom, which advocates for Judeo-Christian religious liberty.