Does the nation still need affirmative action? Here is the big picture.

According to Education Department statistics, there has been no dramatic change since the Supreme Court found in 2003 that promoting diversity on college campuses is a compelling national interest. The share of 18- to 24-year-old whites who are enrolled in college stayed about flat between 2003 and 2015, at 42 percent. African American enrollment in that age group changed only a bit, from 32 percent to 35 percent, continuing to lag whites. Though Latinos gained, from 24 percent to 37 percent, they, too, continue to trail whites in the percentage of college-age people enrolled. Over a longer horizon, African Americans’ progress looks more substantial: College enrollment among black 18- to 24-year-olds in 2015 was up 19 percentage points from 1970. But white enrollment surged a comparable amount over that period, by 15 percentage points.

The typical college campus in the United States is still very white — and the typical university of higher quality, even whiter. In 2014, whites made up the bulk of students in four-year colleges — 58 percent. Meanwhile, the four-year college population was 13 percent African American, up only a point from a decade before, and 12 percent Latino, up a few points over a decade. Whites are somewhat less dominant at two-year colleges, making up 51 percent of the population attending those schools. African Americans account for 15 percent and Latinos 23 percent, higher than their four-year figures.

This is the context in which to consider last week’s news that the Trump Justice Department is preparing to investigate and possibly sue universities with race-conscious admissions policies. The New York Times reported that the goal would be to curb ostensible discrimination against white applicants. A Justice Department spokeswoman indicated that the department was interested in investigating “one admissions complaint” relating to Asian American students.

We hope that is true. Because a wider federal effort challenging affirmative action policies would represent a drastic change in the department’s priorities and, if the idea was to protect whites, a perversion of civil rights law meant to protect disadvantaged minority groups. Though the Supreme Court recently reaffirmed that carefully designed affirmative action policies are legal in public university admissions, the court also left some room for lawsuits claiming that colleges’ race-conscious admissions practices are not narrow enough. If the weight and resources of the federal government are devoted to suing universities, schools could be discouraged from using legal methods to build diverse student bodies.

(Claritza Jimenez/The Washington Post)

In the long term, Chief Justice John G. Roberts Jr. was right when he wrote, “The way to stop discrimination on the basis of race is to stop discriminating on the basis of race.” We blame no American who feels queasy about any policy, particularly at state-run institutions, that considers race in any formal or informal way. The possibility that high-performing Asian Americans may face implicit quotas is particularly troubling. But the nation has not yet made enough progress in clearing paths of opportunity for historically disadvantaged minorities or in building college communities that reflect its rapidly diversifying character. It is as important for minority students who benefit from affirmative action as it is for their white peers that the nation’s universities prepare all of them for citizenship in a polyglot country. The Justice Department should not impede universities’ efforts to do that.