Washington ? The Supreme Court agreed Monday to take up two cases that could spell the end of official efforts to maintain racial integration in U.S. public schools.

The justices said they would hear appeals from parents in Seattle and Louisville, Ky., who say it is unconstitutional for officials to consider a student’s race when making school assignments. Both cities adopted voluntary integration programs in recent years that put limits on how many white or black students may be enrolled in some schools.

A ruling outlawing such efforts could have a wide impact.

Monday’s announcement could signal a historic shift on the role of race in education. Just three years ago, the court upheld affirmative action in colleges and universities, but two new conservative justices have joined the court since then, and both have criticized the use of race by the government.

Beginning with the Reagan era of the 1980s, conservatives have insisted it is unconstitutional for the government to use a person’s race as a factor in hiring, awarding contracts, admitting college students, or, in this instance, assigning students to public schools.

In 2003, however, the Supreme Court dealt conservatives a defeat in a University of Michigan law school case. The court, in a 5-4 decision, said higher education had a “compelling” need to consider a student’s race if it was to maintain diversity in classes.

That decision was written by Justice Sandra Day O’Connor, who retired in February.

Her replacement, Justice Samuel Alito, is seen as likely to take a more conservative stand on race and affirmative action. In 1985, as a lawyer in President Reagan’s Justice Department, he said he was “particularly proud” of the administration’s efforts to persuade the Supreme Court that “racial and ethnic quotas should not be allowed.”

Chief Justice John G. Roberts Jr., who also worked in the Reagan administration, wrote memos that criticized the overt use of race by the government.

“The issue here is: Can public schools voluntary discriminate among students to achieve racial balance?” said Sharon L. Browne, a lawyer for the Pacific Legal Foundation in Sacramento, Calif., which had urged the court to hear both cases.

“They are teaching our kids that race still matters. If they can continue to do that, we will never get to a place where the country is color blind.”

She said as many 1,000 school districts nationwide seek to integrate some schools by enrolling or not enrolling students based on their race.