Supporters of gay marriage, frustrated over a ballot-box defeat in California, have channeled much of their anger toward the towering white spires of Mormon temples.

For months, the Mormon church sought to portray itself as just one member of a coalition of Catholics, evangelicals, black Protestants and others supporting Proposition 8, a measure to stop gay marriage in California.

Some opponents of the measure sought to dispel that in the campaign's final weeks, pointing to extensive Mormon organizing and the staggering amount of money donated by individual Mormons at the behest of church leaders in Salt Lake City.

Since the measure's passage, media outlets reported chants of "Mormon scum" and slurs against church founder Joseph Smith at a demonstration outside a Los Angeles-area temple, and a church meeting-house was vandalized. More Mormon-specific protests are in the works.

The backlash against Mormons has ignited a debate over whether the church deserves to be singled out for what opponents believe was a dishonest campaign or is an easy political target as a minority religion that has taken plenty of lumps.

"I think it is a purely tactical reaction from those who are supporting gay marriage, because if it can be made to appear the opposition is essentially one religion that is, frankly, an often misunderstood religion, it's easier to make the case that the other side is reasonable," said Michael Otterson, a spokesman for the Church of Jesus Christ of Latter-day Saints, or the Mormon church.

Proposition 8 opponents denounced vandalism and violence, and some have spoken out against anti-Mormon rhetoric. They also say Mormon money funded irresponsible ads, such as one suggesting young children would be required to learn about homosexuality in schools.

"I don't think the Mormon church stepped outside the boundaries available to any faith community that wants to get organized on values they hold dear," said Lindi Ramsden, a Unitarian minister who organized interfaith opposition to the measure. "The part that saddens me is that money donated by people of faith was used to finance advertising that is as close to blatant lies as you can get."

Even so, the Rev. Ramsden sent an e-mail to allies this week warning against making scapegoats of any one group, including Mormons and blacks, who also strongly backed the measure.

The Mormon church's Propo-sition 8 efforts represent its strongest push into politics since it opposed the Equal Rights Amendment in the 1970s.

The church believes traditional marriage is best for society. Heterosexual marriage is also central to Mormon theology; Mormons believe their marriages are keys to eternal life.

In June, the LDS First Presidency, its highest governing body, announced its support for Proposition 8 in a letter read at every congregation. Members were asked to donate their "means and time" to the effort to undo a May court decision that legalized gay marriage in California and opened the door for 18,000 same-gender couples to wed in the past four months.

One factor in Mormons becoming an opposition target was Mormonsfor8.com, a Web site founded by Nadine Hansen, a 61-year-old semiretired lawyer from Cedar City, Utah.

Because the church itself did not donate money to the campaign, Ms. Hansen sought to identify Mormon donors of $1,000 or more, matching campaign records to tips from site visitors and church members and what she and others uncovered with search engines.

The site attributes $15 million in donations to Mormons, or nearly half the Yes on 8 war chest in a state where Mormons make up 2 percent of the population.

Originally, the site named Mormon givers, but Ms. Hansen said she changed it to include only first names and last-name initials over concerns Mormons would be hate-crime targets.

"For months, these sacred houses of worship were the precinct offices, members were called to be campaign workers and ward lists were turned into voter rosters," Ms. Hansen said. "Basically, if the church wants to know why Mormon sacred places are targeted, look in the mirror."

Ms. Hansen said she is a Mormon but does not attend church. Mr. Otterson, the church spokesman, said the church recognizes freedom to demonstrate, but hopes it is in "good taste and respectful."

Some gay-marriage backers in California began taking a sharper tone against Mormons in October. The liberal group Courage Campaign organized an online petition asking LDS Church President Thomas Monson to stop bearing false witness, among other things.

On election night, the group aired an ad that depicted Mormon missionaries ransacking a lesbian couple's house and destroying their marriage certificate.