The issue for the justices is whether the statute guards against all discriminatory job transfers or requires an additional showing in court by the employee that the involuntary move caused a significant disadvantage, such as harm to career prospects or a change in salary or rank.

The officer’s position, backed by the Biden administration, is that a separate determination of harm should not be required. She appeared to draw support from a majority of justices on both ends of the bench, who suggested the court should stick to the simple text of the statute — that it is unlawful “to discriminate against any individual with respect to his compensation, terms, conditions, or privileges of employment” because of an individual’s sex.

Discrimination on its own is an injury, several of the justices said, suggesting that judges should not be asking, “how bad is bad enough?”

“When you treat someone worse than another person because of race or sex, that’s kind of the end of it, and there isn’t a further inquiry into how badly you treated somebody,” said Justice Neil M. Gorsuch, a conservative who is among the most adamant of the justices in considering the text of a statute paramount.

Even a relatively minor instance of discrimination on the basis of sex or race, he added, “is something Congress in 1964, in a very short and sweet statute, 28 pages long but profound, said that the law will no longer tolerate.”

Justice Ketanji Brown Jackson, a liberal, and Justice Brett M. Kavanaugh, a conservative, teamed up at one point during the argument to press the lawyer for the St. Louis police department about the implications of his view that an employee must show harm, not just discrimination, to avoid meritless claims.

“The premise of your argument, I think, is that discrimination itself is not harm,” Kavanaugh said.

Jackson followed up, “So discrimination itself is or is not a harm?”

Only Justice Samuel A. Alito Jr. seemed to embrace the idea that there should be a standard to clear before a claim can proceed in court.

“All disparate treatment based on race, sex, et cetera, is wrong,” Alito said. But he suggested there should be “some sort of threshold that has to be cleared before the matter gets into court.”

Jatonya Clayborn Muldrow sued the St. Louis department after she was transferred in 2017 out of the intelligence division, a position that allowed her to be deputized as an FBI agent, work a steady weekday schedule, and broadly investigate public corruption and human trafficking cases.

Muldrow, who attended the argument on Wednesday, said in court filings that her reassignment lacked the same prestige and benefits. Even though her pay remained the same, she lost her FBI privileges, had to work patrol and was assigned weekend shifts. Muldrow, who was known as a “workhorse,” according to court filings, was replaced in the intelligence division by a male sergeant who previously worked with Muldrow’s male supervisor. The supervisor, according to court records, referred to male sergeants according to their rank but referred to Muldrow as “Mrs.”

A District Court judge in Missouri sided with the city, saying Muldrow had not proved that her transfer caused sufficient disadvantage. The U.S. Court of Appeals for the 8th Circuit agreed, finding that Muldrow could not proceed with her lawsuit because she failed to demonstrate that the transfer amounted to an “adverse employment action” that caused tangible harm.

The nearly two-hour argument on Wednesday featured hypotheticals about what counts as discrimination in the workplace, some of which echoed discussions of affirmative action that have polarized the nation in recent years.

Could a law firm seeking to increase the number of women in its leadership ranks promote only women, asked Justice Amy Coney Barrett? What about an employer who gives raises only to the women in the office, posited Justice Elena Kagan? Could a police department move only Black or Latino officers into certain neighborhoods, asked Justice Clarence Thomas?

“When an employment decision is made on the basis of a protected characteristic, that is the denial of equal treatment, and that’s a harm that this Court has recognized in many cases,” Aimee Brown, an assistant to the solicitor general, said in response to Thomas’s hypothetical.

In addition to civil rights groups, the case is being closely watched by employment attorneys and some conservatives who say a broad ruling for Muldrow could lead to an increase in reverse discrimination claims against workplace diversity, equity and inclusion programs.

Thomas asked the federal government’s lawyer whether her position would “run headlong into the focus on diversifying the workforce in certain situations.”

Brown said in response that Title VII permits efforts to ensure a diverse workforce through recruiting, mentorship and other programs.

Civil rights groups and the Biden administration say discrimination claims are too easily dismissed when lower courts have required a separate showing that a workplace reassignment caused significant disadvantage. When an employee proves she was transferred because of her sex, the solicitor general said in court filings, no further showing of harm is required.

Muldrow’s lawyer, Brian Wolfman, emphasized in court Wednesday that the Title VII statute protects individuals not only from discriminatory hiring, firing, or compensation but also from discrimination because of certain characteristics with respect to the “terms, conditions, or privileges” of employment, which he said includes job transfers.

Lawyers for the city, however, said there must be some showing of “objectively meaningful harm” for discrimination claims based on a reassignment or transfer. They said employers need flexibility to make personnel decisions, and they warned against eliminating what they say is an important tool for getting rid of frivolous claims at the early stages of litigation.

Robert Loeb, the attorney representing the city of St. Louis in court, said a decision siding with Muldrow and the Biden administration would turn federal courts into a “super-personnel department” for all private employers, state and local governments. The statute, Loeb said, is not meant to open the door to lawsuits over minor slights or personal preferences.

“You don’t want to micromanage every personnel action,” Loeb said.

Brianne Gorod, chief counsel at the Constitutional Accountability Center, said in a statement after the argument that the case should be an easy one for textualists, which all members of the court, but especially the conservatives, consider themselves to be.

“Holding that Title VII’s protections extend as broadly as the plain text of the law requires,” Gorod said, “would be a win not only for Ms. Muldrow, but also for workers more broadly.”

The case is Muldrow v. City of St. Louis.