Did Blacks and Hispanics defeat California's Proposition 8?

Some claim that blacks probably didn't tip the balance in the vote on California's proposition 8. Others have made similar statements that because of the unusually high turnout among blacks, blacks and Hispanics as a whole made the difference for Proposition 8. 13,084,570 people voted on proposition 8. The initiative won 6,838,107 to 6,246,463, a difference of 591,644 votes. 10 percent of the voters were black (6% black women and 4% black men) and 70 percent of them voted for the proposition. That implies that blacks supplied a net vote in favor of the initiative of 523,383. Blacks by themselves made up 88 percent of the margin by which the initiative won. Hispanics made up 18 percent of the voters and voted for the initiative by 53 to 47 percent. That implies that Hispanics supplied a net 141,313 votes in favor of the initiative.

Minorities supplied a net total of 664,696 votes for the proposition, 12 percent more than was necessary to get it passed. The initiative was clearly passed by black and Hispanic voters. The black support for Proposition 8 appears to have been larger than for any other group, even just 61 percent of those 65 and older supported the proposition.

Next question is whether the large turnout for Obama among minorities made a difference. Historically blacks made up 6 to 7 percent of voters in California and Hispanics about 13 percent. Suppose blacks had made up 6 percent of the turnout this election. That would have reduced the net vote by blacks in favor of the initiative to 314,030. For Hispanics, it would have reduced their net vote to 102,059. A net gain for Proposition 8 of 416,089 votes, about 63 percent of what they contributed. Blacks and Hispanics would have made the difference even if they hadn't turned out in record numbers, but the win margin for the proposition would have been reduced by almost 250,000 votes.