The Bush administration this week marked Martin Luther King Day with a promise to increase spending on grants to historically black and Hispanic universities by 5 per cent.
The announcement came just days after President George W. Bush reignited a national debate about whether race should be considered in university admissions with an emphatic "no", a position with which even some of his top advisers disagree.
Ordering the federal government to file a legal brief asking the US Supreme Court to bar the University of Michigan from using race as a factor, Mr Bush said: "The Michigan policies amount to a quota system that unfairly rewards or penalises prospective students based solely on their race. As we work to address the wrong of racial prejudice, we must not use means that create another wrong, and thus perpetuate our divisions."
The Democrats said they would make equal education opportunity a major issue in next year's presidential election.
Democrat congressman Robert Menendez said Mr Bush was hypocritical, considering that he had got into Yale University despite mediocre grades, probably by virtue of a special preference for the children of alumni.
"We have a president who, on his merit, might not have made it into Yale," Mr Menendez said. "He's now trying to deny African-Americans, Hispanics, Asian-Americans and others the chance to compete with students from private schools in affluent areas."
Two members of the president's cabinet said they disagreed with him.
Secretary of State Colin Powell said he supported affirmative action.
National security adviser Condoleezza Rice said that while there were "problems" with Michigan's selection system, it was sometimes "important to take race into consideration".
A black former member of the faculty at Stanford University, she said she had benefited personally from affirmative action in her career. "There's nothing wrong with that in the US," she said. "It does not mean that one has to go to people of lower quality."
Public universities have begun to consider what they would do if affirmative action was outlawed. Private universities would be unaffected.
Many large public universities give minority applicants extra points on admissions scales, a process that makes it easier and less costly to consider large groups of people without having to check applications individually.
Some have switched to a process under which they admit the top 10 per cent of graduates of each high school in their state. Students in less privileged, predominantly non-white schools would have the same chance as those from wealthier, predominantly white districts.