I've been reading up on this subject over the last few days. Apparently, in recent years the courts have distinguished between what they call "intentional governmental discrimination" and so-called "defacto segregation" (i.e., "white flight"). In general, recent rulings (including this one) suggest that school boards are under little or no compulsion to address "defacto segregation."

However, in this excerpt from a National School Board Association (NSBA) report, below, the NSBA suggests that non-racial factors, including students' socio-economic backgrounds, might be considered in school boards' efforts to create diverse student populations.

Whether it is race or some other factor school boards use to diversify schools, my questions are still these: In the case of "de facto" segregation, whose task is it to correct the problem? If school boards undertake the task of correcting the problem, absent any ability to address
the errant growth plans that created the problem, do they (continually) work against another task understood to be theirs, namely to create "community-based" schools? And finally, at what point should we consider a school "diverse," in terms of some applicable benchmark (I do not know how this "unitary status" the NSBA refers to is defined or measured)?

Link to article:
(link...)

Excerpt:
Conclusion: Making Policies Fit The Law

"The trend in recent cases is to strike down programs that rely solely on race, unless the program is necessary to remedy intentional governmental discrimination. A few jurisdictions recognize other compelling interests
that may justify narrowly tailored race-based programs: the Ninth Circuit (the federal jurisdiction that includes the Pacific states, plus Montana, Idaho, Nevada, and New Mexico) recognizes educational diversity as such an
interest, while the Second Circuit (New York, Connecticut, and Vermont) recognizes a district's interest in preventing de facto segregation. Districts that gear their policies toward the goal of diversity should understand the different legal meanings of that term, and should avoid using race as a proxy for a broader sense of diversity: despite the contrary decisions of a few courts, pure racial balancing is highly unlikely to survive strict scrutiny unless it is necessary to remedy specific constitutional violations. Whatever the rationale for a race-conscious
policy, a district should be prepared to defend it with hard facts. Even districts still operating under desegregation orders should not assume that they have free rein to assign students on the basis of race, but should
consider whether they now meet the conditions for unitary status. Finally, no matter what policy a district puts in place, it should tailor that program narrowly to its stated end and should specifically delineate guidelines and objectives.

A district considering whether to use race in admissions and assignments must at least consider alternative, non-racial criteria that might serve just as well. Apart from passing strict scrutiny, there is another excellent reason for giving non-racial alternatives serious consideration.
If the goal of diversity can be achieved without the use of race, then an admissions or assignment plan can in all probability avoid strict scrutiny and perhaps even prevent litigation over the issue altogether.
Recommendations dealing with higher-education admissions processes may be difficult or impossible for K-12 officials to implement. Yet there are several non-racial factors that could be used to create a meaningfully diverse learning environment. A district might consider such things as a student's socio-economic background, family pattern (raised by grandparents, single parent, and so forth), parents' educational history, English proficiency, free-lunch qualifying status, or neighborhood, for example.
These factors should not be used as proxies for race: although a district that uses them is likely to achieve some measure of racial balance, a policy whose secret intent was race-oriented might receive strict scrutiny even if it did not overtly rely on race. Given recent trends in the courts, many districts may find the next piece of the legal puzzle by re-thinking the nature of student diversity."