Protesters gather outside the Supreme Court last year while justices hear arguments in the Young v. UPS case. (Win McNamee/Getty Images)

Lauren Sudeall Lucas is an assistant professor at Georgia State University College of Law. She writes about the relationship between constitutional rights and identity.

Intersectionality is the acknowledgment that different forms of identity-based discrimination can combine to give rise to unique brands of injustice. For example, although women may generally face certain challenges in the workplace — unequal pay and the “motherhood penalty”  are common — women of color may face different obstacles, including a bigger wage gap and the perception that they are too aggressive.

The Equal Protection Clause is the primary constitutional tool for addressing claims of identity-based discrimination. Finding out whether an incident of discrimination is legal typically begins with identifying the identity category — such as race or gender — on which the alleged discrimination is based. Depending on the category invoked, courts will apply varying levels of analysis to the claim, making it easier or harder for those accused of discrimination to defend their policies.

But for those who face discrimination at the intersection of multiple identity categories, it is not immediately clear how a court should respond. If someone claims that she has been denied the equal protection of the law because she is a black woman, should the alleged discrimination be examined with strict scrutiny, the most stringent standard of review in the court system, which is applied to classifications based on race? Or should it be treated with intermediate scrutiny, the lesser standard typically applied to gender classifications?

The categorical quality of equal protection makes it difficult for the law to acknowledge how certain “identity-relevant” attributes may make certain kinds of discrimination even worse. And it’s an approach that has the potential to render intersectional injury invisible.

Consider pregnant women, who often face distinctive forms of discrimination, particularly in the workplace. At issue in Geduldig v. Aiello, for example, was California’s disability insurance program. It paid benefits to those temporarily unable to work due to disability, but excluded pregnancy-related disabilities from coverage. In analyzing discrimination on the basis of pregnancy in Geduldig, the Supreme Court concluded that although only women can become pregnant, not all women are pregnant. Thus discrimination on the basis of pregnancy could not be assessed with the heightened level of scrutiny applied to distinctions made on the basis of sex, and the state’s policy was allowed to stand. Although the decision was effectively overruled by the Pregnancy Discrimination Act, it has never been overruled by the Supreme Court.

For similar reasons, the Court has refused to provide heightened scrutiny to discrimination on the basis of language. The issue in the case of Hernandez v. New York was whether a prosecutor’s decision to strike Spanish-speaking jurors — intended, the defendant claimed, to prevent Latino jurors from weighing in on his criminal trial — violated equal protection. Finding that language did not necessarily align with race — in the context of that case, there were some Latino jurors who were bilingual and others who were not — the Court held that a higher level of scrutiny did not apply.

Structuring equal protection around identity and deciding to elevate only some categories to a heightened level of scrutiny inevitably raises the question of who is “in” certain categories and who is “out” — who will benefit from additional protection and who will be excluded from it.

It demands, in a sense, that we strictly define the experience of each identity category — what being black or being female looks like, for instance — and when exactly it applies. But doing so will inevitably exclude the experiences of some. Even as the Court has expanded protection to sexual orientation minorities, it has often spoken only of “gays and lesbians,” leaving some to wonder whether that protection applies to transgender individuals.

To avoid being boxed into creating exclusive categories of identity, we should focus on understanding why certain kinds of discrimination are particularly harmful in the first place, and thus deserve a higher level of scrutiny. (Discrimination based on race or gender, for example, is often viewed as particularly troubling because of the role it has played in the context of history and because it isn’t easily addressed through the political process.)

Rather than asking whether certain characteristics — such as pregnancy or language — fit into an identity category that already receives heightened protection, a better equal-protection inquiry might focus on whether there are similar reasons to be wary of discrimination based on that characteristic — or one’s experience at the intersection of several.

Instead of asking whether discrimination is based on race or gender, we should ask whether it serves the same purpose as those kinds of discrimination do — further subordinating a group that is not in a position to prevent such subordination. It becomes less important, then, whether we understand the experience of black women, or pregnant women, or Spanish-speaking Latinos, as one based on “race” or “gender,” and more important that we understand the ways in which the various forces operating on such individuals contribute to their oppression.

Each week, In Theory takes on a big idea in the news and explores it from a range of perspectives. This week we’re talking about intersectionality. Need a primer? Catch up here. Then explore these other perspectives:

Kimberlé Crenshaw: Why intersectionality can’t wait.

Lauren Sudeall Lucas: Why Equal Protection may not protect everyone equally.

Latoya Peterson: Intersectionality is not a label.

Brittney Cooper: Black lives do matter — all of them.

Alyssa Rosenberg: How ‘Orange Is the New Black’ wins at illustrating identity