WASHINGTON (CNN) - A two-day showdown over same-sex marriage began Tuesday.
The Supreme Court heard oral arguments on Proposition 8, approved by California voters, that banned same-sex marriage in that state after courts had previously ruled they were legal.
"They're arguing for a nationwide rule which applies to States other than California, that every State must allow marriage by same-sex couples," said Justice Antonin Scalia.
Lawyers representing the plaintiffs, two unmarried same-sex couples, stated their case by saying that "same-sex couples are considered second rate, different, unequal and not okay."
On the other side, lawyers representing supporters of the Prop 8 ban on same-sex marriage said, "We believe that Prop 8 is constitutional and we believe the place for the decision to be made about redefining marriage is with the people, not with the courts."
A new CNN-ORC poll shows 53 percent of Americans believe marriages between gay and lesbian couples should be recognized as valid, compared to 40 percent who said so in 2007.
Wednesday, the court will hear oral arguments on the Defense of Marriage Act (DOMA), a federal law that defines marriage as a union between a man and a woman.
Rulings in both cases are expected this June.