From the country's heartland, voters sent messages that altered the culture wars in the U.S. and dismayed the religious right -- defending abortion rights in South Dakota, endorsing stem cell research in Missouri and, in a national first, rejecting a same-sex marriage ban in Arizona.

Conservative leaders were jolted by the setbacks and looked for an explanation Wednesday. Activists for gay rights and abortion rights celebrated.

The verdict on abortion rights was particularly clear. Oregon and California voters defeated measures that would have required parents to be notified before a girl under 18 could get an abortion, and South Dakotans -- by 56 percent to 44 percent -- rejected a new state law that would have banned all abortions except to save a pregnant woman's life.

"This was really a rebellion in the heart of red-state, pro-life America, the heart of the northern Bible Belt," said Sarah Stoesz, head of the Planned Parenthood chapter that oversees South Dakota. "It sends a very strong message to the rest of the country."

South Dakota legislators had passed the law expecting it to trigger a court challenge and lead to a possible Supreme Court reversal of the 1973 Roe v. Wade decision legalizing abortion. Abortion-rights leaders said Wednesday that such strategies should be abandoned.

Anti-abortion leaders said the GOP shared some of the blame for the defeat. The Rev. Thomas J. Euteneuer, president of Human Life International, said President Bush and other top Republicans failed to campaign strongly for the South Dakota abortion ban and against the Missouri stem cell measure.

"While South Dakotans fought valiantly to defend their babies, we once again witnessed an almost total lack of support from the national leadership," Euteneuer said.

Janice Shaw Crouse, a conservative analyst with Concerned Women for America, suggested that Republicans -- some of them entangled in corruption and sex scandals -- had lost some of the selling power of the "family values" themes they had pushed in recent elections.

"Families had such high hopes when conservatives were in power; they ended up discouraged, disappointed and disillusioned," she said.

Liberal groups did have some setbacks. Michigan voters approved a ban on some types of affirmative action programs, Colorado and Arizona passed measures targeting illegal immigrants, and seven states approved same-sex-marriage bans, joining 20 that had done so in previous elections.