Prop 2 was passed in November 2006 by a vote of 58%-42%, and the Detroit Free Press reports that in the breakdown, it was "overwhelmingly approved by white voters and overwhelmingly rejected by blacks."
Jennifer Gratz, head of the American Civil Rights Institute which opposes Affirmative Action, initially pushed for the ballot measure after her own lawsuit against the University of Michigan. David Ashenfelter and Dawson Bell of the Free Press write:
Gratz, an honors student from Southgate Anderson High, was denied admission to U-M in 1994, a decision she said was influenced by the university's use of aggressive affirmative action for minority applicants. The Supreme Court ultimately struck down the U-M policies in place at that time, but in a separate case involving the U-M law school said the university could continue to take race into account.
"To me, this is the epitome of an activist court," Gratz said of the ruling. "These justices held onto this ruling for years and released it the day before the holiday weekend. They were hoping they would catch people off guard and not make the news."
The ruling can still be appealed to the entire 6th Circuit Court of Appeals, or to the Supreme Court.