Chicago is a testing ground for some of the left’s biggest ideas about race and education. School systems in the city and nearby suburbs are pushing to hire more Black male teachers, add more Black history and train teachers in concepts like white privilege.

Some of those policies have a strong record of improving student learning, while others lack much track record.

But for the Trump administration, all of it could be against the law.

Now, school districts with programs aimed at lifting up Black students, and others, are finding themselves legally vulnerable. The White House is pursuing a reversal of the federal government’s traditional role on race and schools, going after what it calls “illegal D.E.I.,” or diversity, equity and inclusion. The administration is using the Education Department’s Office for Civil Rights, which was established to protect racial and ethnic minority groups, to try to end programs meant to help some of those same students.

Through executive orders, investigations and threats to cut funding, the government has put what was once a bipartisan movement to address the legacy of slavery and racism on the defensive. Even Republican-leaning states like Florida and Mississippi have teacher recruitment programs intended, in part, to diversify the work force — an idea the administration has called illegal affirmative action.

For 20 years, research has demonstrated that students perform better academically when their teachers share elements of their racial, cultural or linguistic identity. And a broad range of social scientists, policymakers and parents have raised concerns about the lack of diverse male role models, as a response to boys’ struggles with academics and mental health.

But over the past decade, many conservatives began to push more forcefully for colorblind policies. Now, Trump administration lawyers are arguing that when school leaders direct resources to racial groups that remain behind, they discriminate against those that have traditionally been ahead.