As the U.S. Supreme Court stands poised to roll back race-based affirmative action admission policies, colleges and universities may begin considering a new way to cultivate a diverse student body – preferential admissions for poor students.

Such admissions practices are not yet common. But they're gaining traction, especially at schools in the eight states that already ban affirmative action, as a way to capture a similar demographic of students.

"Preferential college admission for qualified low-income students could result in as much or more racial and ethnic diversity than is being achieved by current race-conscious affirmative action policies," said Harold Levy, executive director of the Jack Kent Cooke Foundation, a scholarship organization that supports high-achieving low-income students.

For the second time, Fisher v. University of Texas has found its way to the country's highest court, forcing institutions of higher education, especially elite schools that most heavily depend on affirmative action, to imagine how they would maintain diversity in an affirmative action-free world.

"If we can't do it by traditional affirmative action, this is another route and perhaps a better route," Levy said.

Race-conscious affirmative action has been used for decades to address past inequities and offer students from disadvantaged minority groups – especially African-Americans and Latinos – a better chance at gaining access to college.

But a new report from the Jack Kent Cooke Foundation makes the case that the admissions process is rigged against high-achieving low-income students, and that, at a time when economic diversity has eclipsed race as the primary source of disadvantage, colleges and universities should be giving preference to exactly those students.

Indeed, according to the report, students from families in the bottom economic quartile comprise only 3 percent of enrollment in the most competitive schools. That's in contrast with 72 percent of students in those schools who hail from families in the wealthiest quartile.

The situation has not improved in recent years, Levy argues, especially at the most selective schools, which is where the bulk of affirmative action policies are used.

The federal Pell grant, which is targeted to low-income students, has increased dramatically in recent years. But the report shows that while the percentage of students using Pell grants has increased across nearly all sectors of higher education, it's remained fairly stagnant at the most selective colleges.

In 2000, 16 percent of students in the most selective schools were Pell-eligible compared to 17 percent in 2013, according to data from the U.S. Department of Education.

"If the Supreme Court acts, this will become front and center, and that will be the ultimate stimulus," Levy said.

The argument is especially prescient at a time when economic mobility, many studies show, is becoming more difficult.

For example, the achievement gap between white and black students was once twice as large as the gap between low-income students and their wealthier peers. But today, the report shows, precisely the reverse is true: The income gap is twice as large as the race gap, and growing.

Courtesy of Jack Kent Cooke Foundation

To be sure, many selective institutions have sought to address the lack of low-income students on their campuses by committing to "need-blind" admissions or offering financial aid packages that do not include loans. And some schools are successfully recruiting low-income students.

At Vassar College in New York, for example, nearly a quarter of students receive federal Pell grant tuition assistance. And at Amherst College in Massachusetts, admissions officers have gone to great lengths to woo low-income students.

Critics of preferential admission for poor students, however, argue that income-based policies and affirmative action aren't interchangeable and that eliminating affirmative action will significantly reduce the number of black and Latino students at the country's best schools.

"If you were to move abruptly from a regime from racial affirmative action and abolishing that and seeking to replace with a class-based focus, the impact on the representation of African-Americans in the highly selective colleges would be really quite profound," says Glenn Loury, an economics professor at Brown University in Rhode Island.

Loury, who is African-American, does not oppose the idea of preferential treatment for low-income students. In fact, he has argued that affirmative action should, one day, come to an end – a belief he's taken heat for in the past. But the transition, he says, cannot be hasty.

"The bottom line here is there are just a lot of lower-class white people with test scores that are not so bad," he says. "And if you went color-blind on it and then gave a preference for socioeconomic status, the proportion of blacks at places that are highly selective would go down dramatically."

He's not entirely wrong, says Ben Backes, a researcher at American Institutes for Research who has studied socioeconomic preference admission policies in the University of California system.

After California banned affirmative action in 1998, Backes analyzed data on who applied and who was admitted to the most selective of the University of California schools, including campuses at Berkeley, Los Angeles and San Diego.

He found that the most selective schools, instead of affirmative action, began using socioeconomic preferences, including family income and whether students were the first in their family to go to college. And in doing so, about 20 percent of the loss in minority admissions rates at Berkeley and 30 percent at UCLA were offset by changes in the admissions process.

"At least in the immediate aftermath [of the affirmative action ban], the share of black and Hispanic students did not rebound to what it was before," he says. "But at the same time, there was an increase in first-generation college students and overall it did offset some of the drop that would have taken place after affirmative action was banned and the universities didn't do anything."

However, fears that the nationwide end to affirmative action would drastically reduce the number of minority students attending college are unfounded, Backes says. In states that eliminated affirmative action, he says, only the elite universities are impacted.

"It's not like the average person applying to college is going to be affected by this either way," Backes says. "That said, at those selective public institutions, if you look at what their student bodies look like, they very, very disproportionately come from advantaged backgrounds."

And that's exactly the point Levy and the Jack Kent Cooke Foundation report is trying to make.