Although it is disappointing that slightly more than half of Californians disapprove of the state supreme court decision that overturned the ban on gay marriage, this represents a significant deflation of opposition from 2000, when a ballot initiative banning gay marriage passed with 61 percent of the vote.
Ballot initiatives that pass usually start with higher favorability in polling than 54 percent, which means there is a good chance this measure can be defeated.
The new Los Angeles Times poll found that:

By bare majorities, Californians reject [by 52 percent] the state Supreme Court’s decision to allow same-sex marriages and back [by 54 percent] a proposed constitutional amendment aimed at the November ballot that would outlaw such unions, a Los Angeles Times/KTLA Poll has found.

But the survey also suggested that the state is moving closer to accepting nontraditional marriages, which could create openings for supporters of same-sex marriage as the campaign unfolds.

More than half of Californians said gay relationships were not morally wrong, that they would not degrade heterosexual marriages and that all that mattered was that a relationship be loving and committed, regardless of gender.

Overall, the proportion of Californians who back either gay marriage or civil unions for same-sex couples has remained fairly constant over the years. But the generational schism is pronounced. Those under 45 were less likely to favor a constitutional amendment than their elders and were more supportive of the court’s decision to overturn the state’s current ban on gay marriage. They also disagreed more strongly than their elders with the notion that gay relationships threatened traditional marriage.

If the out-of-state political operatives behind the ballot initiative were hoping to help deliver California to John McCain in November, they may have miscalculated:

Responding to a separate question, only 10 percent of registered voters said that gay marriage was the most important issue facing the state, although more than 5 in 10 voters characterized it as important, just not the most important. Another third of voters said it was not important at all.

Among those who felt it was the most important, more than 6 in 10 were conservatives or those who consider themselves part of the Republican religious base. They were overwhelmingly voting for McCain, the poll found.

Ballot initiatives that pass usually start with higher favorability in polling than 54 percent, which means there is a good chance this measure can be defeated.