The Supreme Court will rule on the constitutionality of DOMA in a ruling expected Wednesday morning. Opponents of the legislation have argued that the restriction on recognizing gay marriages violates the Fifth Amendment's due process clause.
The high court will also examine California's Proposition 8, a statewide ballot initiative banning same-sex marriage. Gay rights activists hope the court will overturn the law, paving the way for same-sex marriages to resume in the state.
CNN polling director Keating Holland said in a statement that shifting attitudes on homosexuality on the whole had driven the nation's change of heart on gay marriage.
"In the 1970s, when polls first tackled this touchy topic, a majority of Americans believed that homosexual relationships between consenting adults were morally wrong, a belief that persisted into the 1990s and the first few years of the 21st century," Holland said.
"But three years ago, the number who felt that homosexual relationships were morally wrong began to drop below 50 percent, and currently 54 percent of the public says that homosexual relationships are not a moral issue. Not surprisingly, that shift in opinion coincided with a growth in support for same-sex marriage."