The state of Michigan, which has already spawned two leading Supreme Court cases on affirmative action, may be heading for another showdown on the issue at the ballot box next fall.

Voters will likely take up a ballot measure that is intended to end the affirmative action program that the high court upheld in 2003, when it ruled in Grutter v. Bollinger that the University of Michigan’s law school could use race as a factor in admissions in order to promote diversity in its student body.

On Tuesday, the Michigan Court of Appeals ordered that a proposed constitutional amendment to ban all government-sanctioned race and gender preferences be placed on the November 2006 ballot.

The court’s action followed a raucous meeting last week at which a state elections board failed to comply with an earlier court order requiring the certification of ballot petitions. The December 14 meeting of the state’s Board of Canvassers in Lansing was disrupted by hundreds of student protesters who urged the panel to defy the court’s instructions.

“They say Jim Crow, we say, hell no!” the demonstrators chanted, according to the Associated Press. As the board prepared to vote, the group surged forward and knocked over a table, prompting a recess while police restored order. One woman was arrested.

Opponents of the ballot measure claim paid signature-gatherers lied to voters about what the constitutional amendment would accomplish. A spokesman for a group that helped organize the protest, By Any Means Necessary, said those involved in obtaining the 450,000 signatures on the petitions told voters that the measure would preserve affirmative action programs. “We’ve had numerous people come forward and say they were deceived,” the spokesman, Luke Massie, said. “One quarter of their signatures came from overwhelmingly black areas of Michigan and they did so by deceiving people as to the purpose and intent of their initiative.”

A California-based, anti-affirmative action advocate who is backing the Michigan initiative, Ward Connerly, told The New York Sun he was outraged by the suggestion that African Americans did not understand the language of the measure. “My skin color is brown. I don’t support race preferences. Maybe other people in Michigan felt the same way,” he said. “That’s racist to presume that black people cannot read and cannot make judgments about what they read. The language is on the petition, whether you’re black or white or purple or green, it was there for you to see.”

Mr. Connerly is a land development consultant best known for spurring passage in 1996 of a California ballot measure, known as Proposition 209, that banned the use of race and gender preferences in state employment, contracting and education. He said he personally gave about $450,000 to the effort to get a similar proposal before Michigan voters, while a group he heads, the American Civil Rights Coalition, gave about $600,000 to $700,000.

The looming battle over the Michigan initiative has led to some curious alliances and divisions. Unsurprisingly, leaders of the Democratic Party, labor unions, and traditional civil rights groups have denounced the measure. However, the anti-preference initiative is also being opposed by top Republicans and some of Michigan’s largest employers. A veteran GOP activist who is running for governor, Richard DeVos Jr., has come out against the measure, as have two Republican senatorial candidates, Michael Bouchard and Keith Butler. Only one Senate candidate, Jerry Zandstra, has endorsed the proposal to end preferences based on race, gender, and ethnicity.

Mr. Connerly said the Republican candidates have made strategic decisions to oppose the initiative. “It’s political. Their calculation is this initiative is going to win and they want to try to position themselves to be in the center,” he said. “It’s almost a blessing to have Republicans out against us because we can truly say this is a nonpartisan issue and that’s the way we want it.”

Meanwhile, the disruptive tactics of Mr. Massie’s group, By All Means Necessary, have led to it being disowned by the main coalition arrayed against the measure, One United Michigan. “There’s a radical group out there we do not condone,” a spokesman for One United Michigan, David Waymire, said. “We do not work with them.”

Mr. Massie called the assertion that the two groups are unrelated “not entirely true.” He declined to elaborate.

Mr. Waymire said his organization has joined together the Detroit business community, including the major automakers, as well as interest groups who might not have been expected to weigh in, such as the American Association of Retired Persons. “We have formed a giant coalition,” he said. “In California, the Republicans were on the other side.”

In a poll taken last year for the Detroit News, 64% of registered voters favored eliminating affirmative action programs, while 23% wanted to retain them. Mr. Waymire said his group plans to air television and radio advertisements to erode support for the initiative in advance of next year’s vote. “If we can inform people, we win,” he said. “The problem we have here is the language that they have is extremely deceptive on purpose.”

Mr. Waymire said the initiative would end programs to encourage women to study science and others to urge men to take up nursing. He said women’s sports programs could be in jeopardy if the federal government makes changes to its requirements.

Mr. Connerly said the claim that sports programs could be disrupted was “nonsense” and part of an effort to refocus the debate on gender, instead of race. He also rejected criticism that, as a Californian, he is meddling in Michigan’s affairs. “The whole civil rights movement was led over the years by people who were not residents of Birmingham, or wherever,” he said. He noted that the initiative is backed by people with ties to Michigan, such as a liberal University of Michigan philosophy professor, Carl Cohen, and the plaintiffs in the two recent Supreme Court cases, Jennifer Gratz and Barbara Grutter.

With an intense campaign ahead, Mr. Connerly offered a truce of sorts to those who have painted him as an interloper. “I’ll stay away, if Al Sharpton and Jesse Jackson will,” he said.