Proposition 8 was a ballot proposition in California that added the following text to Section 7.5 of Article I of the California Constitution: Only marriage between a man and a woman is recognized in California.  It sought to return traditional marriage to the state. The proposition passed with 52.3% of the vote on November 4, 2008.
The proposition only affected whether same-sex couples could call themselves married under California law, and did not affect any substantive rights. Same-sex couples can still file joint state tax returns, adopt children, and enjoy other marital benefits under the California domestic partnership law. They could not call themselves married under federal law anyway, and the federal government does not recognize any same-sex marriages.
After the election, demonstrations and protests occurred across the state and nation. Numerous lawsuits were filed with the California Supreme Court by same-sex couples and government entities, challenging the proposition's validity and effect on previously administered same-sex marriages. The court heard oral arguments on March 5, 2009, and declared Proposition 8 unconstitutional on August 4, 2010.
History of Marriage in California
Historically marriage in the state of California had always been between a man and a woman as that was the understood definition of marriage. There was no need to include language that specified gender. In 1977, amidst a changing climate that saw the advent of the gay rights movement, the California legislature amended the California Family Code to make it clear that marriage was between a man and a woman. 
In 2000 the possibility of same-sex marriage being legalized in other states led to Proposition 22 being passed, adding language to restrict California from recognizing the marriages of same-sex couples from other states as valid.  Proposition 22 passed easily with 61% of the vote, but it was overturned by California's Supreme Court in May of 2008. The court also mandated that same-sex marriage licenses be issued by judicial degree, not by the will of the voters or the legislature. The licenses were not recognized by the federal government and most of the nation.
The Campaign for Proposition 8
Proposition 8 was written in anticipation of four California Supreme Court Justices who overturned the will of the people and sought to redefine traditional marriage in California.
With a total of over 70 million dollars being spent, it became the most expensive campaign on a social proposition in history. The campaigns for and against Proposition 8 raised $39.9 million and $43.3 million, respectively.
The measure passed with 52% of the votes being for to 48% against. While much was made of the fact that it was losing in the polls up until the time of the election, proponents pointed out that similar measures were often reported as polling poorly, but the actual vote was different. For instance Proposition 22 was supposed to be too close to call in 2000. Although it had been claimed that minority voters were against the message, exit polling on election day showed that latinos favored it overall while blacks favored it with a 70% yes vote. The large number of blacks who came out to vote for Barack Obama helped to tip the scale for Proposition 8's passing. Obama ironically stated that he did not support same-sex marriage, though also against Proposition 8.
ProtectMarriage.com was the main proponent of the measure. It sponsored the initiative that placed the proposition on the ballot and spearheaded the campaign.
- Presidential-nominee and Senator John McCain
- Vice presidential-nominee and Governor Sarah Palin
- Former Speaker of the House Newt Gingrich
- California State Senator Tom McClintock
- Rick Warren
- Roman Catholic Church
- Knights of Columbus
- The Church of Jesus Christ of Latter-day Saints
- Union of Orthodox Jewish Congregations of America
- Eastern Orthodox Church
- Grossmont Union High School District
Equality For All, which ran NoOnProp8.com was the lead organization in opposition to Proposition 8.
- Then-presidential nominee and Senator Barack Obama
- Then-vice presidential nominee and Senator Joe Biden
- California Republican Governor Arnold Schwarzenegger
- House Speaker Nancy Pelosi
- Senator Dianne Feinstein
- Senator Barbara Boxer
- Mayor Gavin Newsom
- Mayor Antonio Villaraigosa
- California Attorney General Jerry Brown
- Apple Inc.
- Los Angeles Unified School District
- California Teachers Association
- Eight of the state's largest newspapers plus The New York Times
Proposition 8 passed with a 52.30% majority (7,001,084 votes) over a 47.70% minority (6,401,482 votes) with 340,611 invalid or blank votes. 79.42% of the Californian population turned up to vote on voting day.
Ron Prentice, the chairman of ProtectMarriage.com issued a statement saying, ""The people of California stood up for traditional marriage and reclaimed this great institution." The organizers of the "No on Prop 8" campaign issued a statement on November 6 saying "Tuesday’s vote was deeply disappointing to all who believe in equal treatment under the law."
Vandalism and Protests
Supporters of same-sex marriage vandalized some "Yes on 8" signs, sent hate mail, and ultimately made death threats which caused at least one top supporter of Proposition 8 to hire a bodyguard. Ultimately the realization that the people had spoken led to protests and arrests. Continuing protests months after the election have led to more issues. The Holy Redeemer Catholic Church was vandalized with the words Prop H8 and a Nazi swastika in spray paint.  The slang H8 stands for 'Hate' or Proposition Hate.
Due to the text that Proposition 8 added to the states constitution, same-sex marriage licenses are no longer being issued in California.
California Attorney General Jerry Brown has argued that the 18,000 same-sex marriages that were performed before Proposition 8 passed should still be considered valid in California. Others have postulated the marriages may be converted to domestic partnerships , which in California have the same state-law rights as marriage. Regardless of the court, any California couple can convert to a domestic partnership any time the couple wishes.
Following the passage, a group of gay couples and governmental entities (a small collection of coastal cities and counties) have filed suit against Proposition 8. The California Supreme court accepted the three lawsuits which sought to overturn Proposition 8 (Strauss v. Horton, Tyler v. California, San Francisco v. Horton). According to the AP, "All three cases claim the ban abridges the civil rights of a vulnerable minority group. They argue that voters alone did not have the authority to enact such a significant constitutional change." Similar laws upholding traditional marriage had already been passed in 30 other states.
The sponsors of Proposition 8 asked the California Supreme Court on December 19th to no longer recognize the alleged marriages of the estimated 18,000 same-sex couples who exchanged vows before voters approved the ballot initiative that said that same-sex marriages were not to be recognized.  "Proposition 8's brevity is matched by its clarity. There are no conditional clauses, exceptions, exemptions or exclusions,".
Oral arguments were heard March 5, 2009, and the decision was rendered May 26, 2009. The California Supreme Court voted to uphold the proposition, but maintain state recognition of same-sex marriages already performed.
A group of Hollywood actors led by musical theater composer Marc Shaiman wrote “Prop 8: The Musical.” The music video mocks Christians, defames Christ, and distorts the teaching of the Bible through a series of "pick and choose" doctrines. Marc Shaiman is also the composer for “Hairspray” and “South Park: Bigger, Longer & Uncut.” 
Chief Judge Vaughn R. Walker of the San Francisco 9th Circuit District Court declared Proposition 8 unconstitutional on August 4, 2010. "The judge found that the gay marriage ban violate[d] the [Federal] Constitution's due process and equal protection clauses." The case is currently under appeal.
- Voter Information Guide, Proposition 8 
- Prop 8 Ruling FINAL Scribd, August 5, 2010.
- UC Berkeley Institute of Governmental Studies, Same-Sex Marriage in California - Overview and Issues
- California Voter Guide, Limit on Marriages. Initiative Statute. Text of Proposition 22  Section 308.5 was added to the Family Code, to read, "Only marriage between a man and a woman is valid or recognized in California."
- "Donors pumped $83M to Calif. gay marriage campaign", The Associated Press, 2009-02-02. Retrieved on 2009-02-03.
- Blacks, Latinos helped Prop. 8, exit polls say
- ABC 30HD, Fresno, CA. "Prop 8 Threat: Fresno Police close to Arrest"
- FoxNews.com, Several Gay Marriage Ban Protesters Arrested in Clashes With Police in California, Thursday, November 06, 2008 
- Cross-Bearing Woman Says She Was Attacked by Gay Marriage Supporters, May Press Charges
- San Francisco Catholic Church Attacked by Pro-Homosexual Marriage Vandals CNSNews, January 13, 2009
- ACLU:California Will Honor Marriages of Same-Sex Couples Married Before the Possible Passage of Prop. 8, Initiative Would Apply to Future Marriages, 11/5/2008
- The Volokh Conspiracy, What Will Happen to California Same-Sex Marriages?, Eugene Volokh, 11/5/2008
- Concurring Opinions,A small wrinkle regarding the Volokh proposal on Prop 8 retro-activity, by Kaimipono D. Wenger, 11/5/2008
- AP, Calif. Supreme Court to take up gay marriage ban, Nov 19, 2008 
- Prop.8 sponsors seek to nullify 18K gay marriages AP, December 19, 2008
- Group Calls for Hollywood to Apologize for ‘Prop 8: The Musical’ CNSNews, December 4, 2009
- Federal Judge Overturns California's Same-Sex Marriage Ban FoxNews.com, August 4, 2010