On Thursday, North Carolina became the first state to require transgender people to use restrooms assigned to the sex on their birth certificate. This week, we learned North Carolina will become the first state to have to defend that law in federal court.

The American Civil Liberties Union, Lambda Legal and Equality North Carolina are suing the state less than a week after its Republican-controlled legislature passed a law aimed at overriding a Charlotte non-discrimination ordinance aimed at granting protections for LGBT residents, including the ability to use the restroom that corresponds to their gender identity. The law forbids other municipalities from enacting their own LGBT protections -- a move its sponsor, Rep. Dan Bishop, said was necessary under North Carolina's Constitution to stop Charlotte's ordinance from taking effect this week.

North Carolina Attorney General Roy Cooper (D) said Tuesday that he won't defend the state against the lawsuit. Cooper is challenging GOP Gov. Pat McCrory in November in what is shaping up to be a competitive race.

What happens next is anyone's guess, because a law of this scope is unprecedented, as is the lawsuit challenging it. But LGBT advocates hope it will at least fire a warning shot at the other states considering their own versions of the restroom legislation. Greg Wallace, a law professor at Campbell University, questions whether gay rights advocates even have a case, as North Carolina is now joining 32 other states that also don't have specific non-discrimination protections on the book for gay and transgender people.

"It really puts North Carolina pretty much in the mainstream of non-discrimination laws," he said. 

The Fix spoke to Tara Borelli, a lawyer with Lambda Legal who is involved in the lawsuit, to better understand what the lawsuit says and how this could all play out.

THE FIX: What's the one-sentence takeaway for this lawsuit? Perhaps that, at its core, this lawsuit alleges that North Carolina just legalized discrimination?

BORELLI: This is a dangerous and unprecedented law. Those two words are some of the best to describe it. [In 1996], Colorado enacted a law that said there could be no statewide protection whatsoever for lesbian, gay, bisexual people. The law was so clearly aimed at lesbians and gay people that the Supreme Court didn't have any trouble striking it down as being clearly motivated by animus against them.

This law goes further because it says there are no protections for transgender people. Even more than that, the law specifically requires discrimination against them in all schools and all public agencies.

THE FIX: The law's supporters point out businesses can still set up their own restroom policies and public or private facilities can still provide unisex restrooms. So how does this law discriminate against transgender people?

BORELLI: This law is treating transgender people different based on their sex. When you take somebody who is male and force them into the women's restroom, it tells everybody they are transgender and subjects them to harassment and violence. That's a profound violation of rights.

Our client Joaquin works for the University of North Carolina. He works in a building that has no unisex bathrooms. There are only women's and men's bathrooms, so when he complies with the law, he has to go into a women's bathroom even though he is male, and everybody recognizes him as male. That will out him as transgender.

Our other client, Payton , when he has in the past tried to use a women's restroom, he was pushed and kicked. These are not hypothetical abstract fears.

THE FIX: You make the argument that this law violates the constitutional right of equal protection and due process. Talk to me about that.

BORELLI: The law says all public schools and all public agencies have to be forced to use bathrooms in accordance with their "biological sex." But it's not a viable option for many transgender people, especially since every jurisdiction has a different set of often onerous and unnecessary requirements for updating gender on a birth certificate. In North Carolina, a person can only update the gender marker on their birth certificate with proof of certain surgeries that may not be necessary, medically advisable or affordable. Tennessee makes it impossible to change the gender marker; the state simply forbids it for a transgender person.

This is also a violation of liberty and the right to refuse unwanted medical treatment by forcing people to choose between surgery where it's required to change their birth certificate and the ability to access restrooms that match their gender.

THE FIX: The law's supporters say they pushed this law through in a day because it was the only way to ensure North Carolina residents' privacy before the Charlotte ordinance took effect. You argue that lawmakers were actively trying to discriminate against LGBT people. How do you make that case?

BORELLI: They were content to allow Charlotte's non-discrimination ordinance to remain on the book for decades, and it was only when Charlotte acted to protect LGBT people that the legislature rushed into the special session and eliminated those protections for LGBT people while simultaneously acting to make sure that other kinds of discrimination would be prohibited. It's pretty stark.

THE FIX: The lawsuit also argues the law violates Title IX (the federal statute requiring equal treatment of sexes in schools). The law's supporters say Title IX has not historically dealt with gender issues; what's your claim? 

BORELLI: .  The federal government has taken a number of actions to make clear its view that discriminating against transgender students with respect to restroom use violates Title IX. In two recent settlements, the [Department of Justice] and the Department of Education have affirmed that equal treatment is required in the form of access to the appropriate restrooms for transgender students. In 2013, the DOJ entered a settlement agreement with a California school regarding the school’s refusal to allow a transgender male student to use the boys’ restrooms and locker rooms.