A federal judge dismissed a lawsuit Tuesday challenging the constitutionality of Proposal 2, the 2006 statewide referendum that banned race and gender affirmative action in public university admissions and government and public school hiring and contracting.

"To impugn the motives of 58% of Michigan's electorate, in the absence of extraordinary circumstances which do not exist here, simply is not warranted on this record," U.S. District Judge David Lawson said in a 55-page ruling, adding that there is no evidence the proposal was enacted with discriminatory intent. "Proposal 2 does not violate the United States Constitution."

The Michigan Attorney General's Office said it is pleased with the decision.

"We're glad to see the federal court upheld the will of the people," said Rusty Hills, a spokesman for Mike Cox. "The attorney general supported Proposal 2 from its very inception."

But Detroit lawyer George Washington vowed to appeal.

"We're appealing immediately," said Washington, who sued on behalf of the Coalition to Defend Affirmative Action and a group of Black and Latino students from Detroit who said they were denied university admission because of Proposal 2. "We don't think in the 21st Century that laws should be passed that are intended to have the effect of excluding black and Latino students from the universities in this state."

Michigan ACLU lawyer Mark Rosenbaum, who also sued on behalf of high school and college students and university professors, said the ACLU would discuss its options.

"It's a real disappointment," Rosenbaum said. "This really stacks the deck against kids of color. ... The reality is that kids of color are going to be severely disadvantaged at state universities in Michigan because they are going to be defined by their racial identities. Every other applicant can define himself or herself as being part of a diverse student enrollment except kids of color."

Michigan voters approved Proposal 2 in November 2006 by 58% to 42%.

Jennifer Gratz, former executive director of the Michigan Civil Rights Initiative, the proposal sponsor, said she is pleased with Lawson's decision.

"Despite numerous attempts to thwart the will of the voters by the radical group By Any Means Necessary and their allies, the people of Michigan will finally have their voices heard," she said. "Fairness and equality are now unequivocally Michigan law."