[Read the statement of interest.]

The Justice Department has increasingly used such statements of interest to intervene in civil rights cases. Before 2006, such statements appeared only seven times in civil rights-oriented disputes, according to a recent paper by law school student Victor Zapana. From 2006 to 2011, they were drafted in at least 242, almost all by the Obama administration on issues such as videotaping police brutality and ensuring that blind people and their service dogs have access to Uber.

But the Trump administration is turning the same tool against affirmative action in college admissions, a major — and highly contentious — legacy of the civil rights era, and one that white conservatives have opposed for decades. In the past few years, the anti-affirmative action cause has been joined by Asian-Americans who argue that they are being held to a higher standard, losing out on coveted slots at places like Harvard as African-Americans, Latinos and other groups get a boost.

A handful of states already ban public universities from relying on affirmative action, pushing several toward a model that takes socioeconomic factors into account instead of race. Public universities in California and Washington have tried to engineer class-based diversity in their student bodies, believing that giving a lift to lower-income students will end up bringing in more minority students as well.

But these methods have not produced classes with an ethnic makeup that mirrors that of the states where they have been used, and many selective private universities continue to admit students partly on the basis of race — though, until Harvard was forced to detail its internal admissions policies recently, few could say how elite universities actually weighed applicants’ race.

Now, universities that factor race into admissions have found a powerful new opponent in the Trump administration, which argued in its filing on Thursday that the court should deny Harvard’s request to dismiss the case before trial.