WASHINGTON — Over the past four years, the Equal Employment Opportunity Commission has extensively and repeatedly pressed the case for expanding the interpretation of existing civil rights protections to cover discrimination against LGBT people.

The Obama administration has supported the broad goals of the EEOC. It has, however, been slower to adopt the independent agency’s specific means of doing so.

The EEOC decided back in 2012 that the sex discrimination ban in the Civil Rights Act of 1964 bars anti-transgender discrimination. The Obama administration eventually agreed with that position in late 2014, a position that has been applied to other laws, including federal education nondiscrimination law, and in recent months has received heavy media coverage.

The question that remains is whether the Obama administration will take the final step previously taken by the EEOC: arguing that sexual orientation-based discrimination also should be barred under existing civil rights laws that ban sex discrimination.

On Tuesday, amicus — friend of the court — briefs are due in a key case pending in the federal appeals court in New York. In his case against Omnicom Group, Inc., Matthew Christiansen argues that the appeals court should follow the EEOC’s interpretation and hold that “sexual orientation is inherently a ‘sex-based’ consideration that deserves Title VII protection.”

The EEOC reached that decision a little less than a year ago, in July 2015, although it had signaled before then that it was headed in that direction.

The trial court judge in Christiansen’s case ruled against him on this point, but U.S. District Court Judge Katherine Polk Failla also wrote that she was bound by a prior decision from the 2nd Circuit Court of Appeals ruling that sexual orientation-based claims are not a type of sex-based discrimination. She did not, however, think that ruling was correct — and urged the appeals court to “erase[]” the line between the two types of discrimination that was previously drawn by that court.

Noting the EEOC’s ruling in the matter and what Failla called the “impracticability” of treating sexual orientation discrimination as a “categorically” different thing than sex discrimination, she wrote that “one might reasonably ask — and, lest there be any doubt, this Court is asking — whether that line should be erased.”

Christiansen appealed the decision and asked that the 2nd Circuit to do just that, filing his brief on June 21. A win in the appeal would allow him to return to the trial court and argue that Omnicom discriminated against him because he is gay. Under the appeals court’s rules, briefs supporting his appeal are due Tuesday.

In another case, involving the gender identity-based discrimination interpretation of existing law, the Obama administration weighed in with a brief supporting Gavin Grimm, a transgender Virginia student. Asked whether the Justice Department would be weighing in this week with a similar amicus brief in Christiansen's case, a spokesperson told BuzzFeed News on Friday evening that the department declined to comment.

Other parties are expected to file amicus briefs in support of Christiansen, as those supportive of the EEOC’s interpretation seek to expand the protections against sexual orientation-based discrimination from the EEOC, which is only binding on federal agencies, into the courts, which would make the interpretation binding on private businesses as well.

Among the expected amicus briefs is one from members of Congress, and House Minority Leader Nancy Pelosi will be among the signatories on the brief. Support was sought from both House and Senate co-sponsors of the Equality Act, a Democratic aide told BuzzFeed News on Sunday, but it was not clear at this point how many members would sign onto the brief. The EEOC itself also is likely to weigh in, as it did earlier this year in a similar appeal before the 11th Circuit Court of Appeals. LGBT advocacy groups also are expected to weigh in with support of Christiansen.

Like the question of transgender protections under current law — fights under way in courts now between the Obama administration and several states — the issue of the interpretation of existing laws to include sexual orientation-based discrimination could enter into the campaign season.

In a position paper made public in December 2015, Hillary Clinton’s campaign states that she “[s]upport[s] efforts underway in the courts and federal government to clarify that under federal statutes ‘sex discrimination’ includes discrimination on the basis of ‘gender identity’ and ‘sexual orientation.’” Asked this weekend if that would include urging the Justice Department to file an amicus brief in a case like Christiansen’s appeal, a spokesperson simply reiterated the line from the position paper and would not respond to a follow-up question seeking further clarification.

A spokesperson for Donald Trump’s campaign did not respond to a request for comment on the issue.

The EEOC is currently settling one of the first cases the agency filed that alleged that sexual orientation-based discrimination is covered by Title VII’s sex discrimination ban. On June 23, the parties in the EEOC’s case against Pallet Companies agreed to a proposed settlement in the case, which they submitted to the federal court in Maryland.

Under the terms of the proposed settlement (a consent decree), the woman who had brought her discrimination claim to the EEOC, Yolanda Boone, is to be paid more than $175,000 in back pay and damages — although the company admits no fault. Under the agreement, Pallet Companies also agreed to pay money to the Human Rights Campaign in support of the LGBT rights group’s Workplace Equality Program.