(AP Photo/Evan Vucci)

On Tuesday, the Obama administration endorsed an amendment that would expand the Civil Rights Act of 1964 to protect gay and transgender Americans. As of yet, there is no federal law that explicitly prevents people from being fired, evicted, or refused service on account of their sexual orientation or gender identity. A proposal just to ban employment discrimination for LGBT Americans has been continuously stymied since 1994.

The Equality Act, which the White House announced it would support Tuesday, aims to provide a wider range of protections, and in the most direct way possible.  The bill would insert language about gay and transgender people into legislation created by the 1964 Civil Rights Act — the historic measure that banned many forms of discrimination by race, color, religion, sex or national origin.

Some LGBT activists have been hesitant to tinker with a law of such stature; the long-deferred Employee Non-Discrimination Act, for instance, is a standalone proposal. Some think that the Employee Non-Discrimination Act would have a better chance of passing if it didn’t try to protect transgender people. In contrast, the Equality Act seeks more potent symbolism by adding LGBT rights to one of the most celebrated civil rights laws in American history. “Does it make sense to have over here in one box, if you will, gender and race and ethnicity, and then put in a separate box LGBT issues?” co-sponsor Sen. Jeff Merkley (D-Ore.) said on the Michelangelo Signorile Show earlier this year.

Interestingly, though, transgender people may already be protected by the 1964 Civil Rights Act. The language of the law bans discrimination by “sex,” and in 1989, the Supreme Court said this meant that employers cannot discriminate against women for not acting feminine enough. Legal scholars say that the precedent against “sex-stereotyping” may extend to transgender people, if they are discriminated against because they do not behave according to the sex assigned to them at birth.

This interpretation has been gaining traction since the 1990s, when transgender plaintiffs began winning employment discrimination trials. The Obama administration has also ratified this legal argument in at least some circumstances. The Equal Employment Opportunity Commission, the federal agency empowered by civil rights laws to police employment discrimination cases, announced in 2012 that the 1964 Civil Rights Act also bans workplace discrimination against transgender people. In a memo last December, Attorney General Eric Holder announced that the Justice Department officially agreed with that opinion.

As a result of those actions, federal employees now have some protection against transgender discrimination. (Federal employees and contractors are also protected by executive order.) Private-sector employees are more at risk, because the EEOC has to make its case against private employers in court. And although many judges have found this legal theory persuasive, the Supreme Court has not yet taken up the specific issue.

By this same logic, the 1964 Civil Rights Act may also extend some protections to gay Americans. If a gay woman is fired because she has a short haircut and doesn't wear makeup, that, too, could be considered sex discrimination. But this is a narrower kind of protection because it doesn't apply when gay people are fired simply for being gay.

(And it should be noted again that to the degree that the Civil Rights Act already applies, we're talking about employment decisions, not housing or public accommodation.)

The EEOC claimed in July that sexual orientation itself should be protected under the sex-discrimination provisions in the 1964 Civil Rights Act, but so far, courts have been more skeptical of this argument. Judges point out that Congress probably did not expect the 1964 Civil Rights Act to be used to protect transgender or gay people. Its persistent decision not to enact the Employee Non-Discrimination Act is further evidence that today’s Congress is not prepared to affirm LGBT rights against discrimination.

The Equality Act, of course, is even less likely to make it through Congress. But the bid to rework a landmark civil rights law starts to seem less audacious in light of the context. If, as some say, the law already implies some protections for LGBT Americans, then the Equality Act would only be making those promises explicit.