Legal battles over whether same-sex couples should be allowed to marry in California have been waged for a decade. The latest twist came yesterday, when a California judge overturned Proposition 8, a ballot measure passed in 2008 saying that marriage had to be between a man and a woman. The judge said Proposition 8, which was passed by 52 percent of California voters in 2008, is unconstitutional. Advocates of same-sex marriage are celebrating the overturning, but the fight is far from over.

Those who believe marriage should only be between a man and a woman say yesterday's ruling in California could lead to legal challenges from other states that don't currently allow same-sex marriage. Many analysts think the case could be headed to the Supreme Court where, if same-sex marriage is deemed legal, the current marriage laws in 45 states could be overturned in a landmark ruling.

Currently, five states, plus the District of Columbia, allow same-sex couples to marry. More than 40 states define marriage as between a man and a woman.

The first 4 minutes and 15 seconds of this video provides an overview of the Proposition 8 ruling; the rest is a conversation with NewsHour Correspondent Spencer Michels, who reports from California.

"The people are the supreme power in California. They created the judiciary. They created the legislature, and they control the Constitution. And they have decided that marriage should be between a man and a woman." - Frank Schubert, Proposition 8 Campaign Manager

"Today, every American should be proud. For so long, Sandy and I and our family have been regarded as less than, unequal, not worthy of liberty and the pursuit of happiness under the law. But this decision says that we are Americans, too. We, too, should be treated equally. Our family is just as loving, just as real, and just as valid as everyone else's." - Kristin Perry, plaintiff

1. What is marriage?

2. What does it mean when someone is gay?

3. What is a ballot measure?

1. Do you think Proposition 8 should have been overturned? Why or why not?

2. Why do you think this issue is so controversial?

3. What are some other landmark court cases that were extremely controversial at the time? Does the controversy continue?