The Trump administration has rescinded Obama-era guidance encouraging colleges to take a student’s race into account to promote diversity in admissions, as part of a broader purge of guidelines issued by prior administrations.

Six pieces of guidance related to affirmative action issued between 2011 and 2016 were among 24 nullified on Tuesday by the attorney general, Jeff Sessions, who said they were “unnecessary, outdated, inconsistent with existing law, or otherwise improper”.

The Obama-era guidance had argued that while race should not be the primary factor in an admission decision, colleges could lawfully consider it in the interests of improving diversity. The documents, which were jointly-released by the departments of justice and education, also argued that colleges and universities had a “compelling interest” in “obtaining the benefits that flow from achieving a diverse student body”, and outlined the options colleges could take under law in pursuit of that goal.

Kristen Clarke, the executive director of the Lawyer’s Committee for Civil Rights called the decision a “politically motivated attack on affirmative action” and a “deliberate attempt to discourage colleges and universities from pursuing racial diversity at our nation’s colleges and universities”.

The move fits into a broader context of Trump administration reversals of a number of Obama-era education policies and regulations. The education secretary, Betsy DeVos, has also recently delayed the implementation of an Obama-era rule intended to address the disparities in the treatment of students of color with disabilities.

In total, Sessions announced the rescission of 24 guidance documents, almost all from the Obama era, which advised on issues such as national origin discrimination, the rights of refugees to work and the detention of juveniles in adult jail facilities.

These types of non-binding directives have been a popular tool for administrations to weigh in on the issue of affirmative action on campus. The Obama guidance itself was a revision of a 2008 Bush administration directive that called racial classifications “highly suspect” and concluded that their use in admissions decisions was “impermissible unless they are ‘narrowly tailored’ to meet a ‘compelling governmental interest’.”

None of the three directives have any legal bearing on what colleges and universities may or may not choose to do with regards to affirmative action in admissions. Colleges could potentially use the new Trump revisions to help defend themselves against lawsuits over their admission policies, however.

The supreme court narrowly upheld the premise of race-based admissions 4-3 in the 2016 case of Fisher v Texas, but the decision is now vulnerable to being overturned with the impending retirement of Justice Anthony Kennedy. The president has said he will name his pick for Kennedy’s replacement on Monday.

Traditionally a “swing” vote between the court’s liberal and conservative camps, Kennedy wrote the opinion in Fisher but it’s unlikely any future Trump appointee would vote the same way the next time a similar case reaches the court.

Eight states already prohibit the use of information on race in public college admissions: Arizona, California, Florida, Michigan, Nebraska, New Hampshire, Oklahoma and Washington.

Tuesday’s move comes as the administration has signalled support for a student group that accused Harvard University of discriminating against Asian-Americans in its admissions process.