A number of legislators, including Sen. Rob PortmanRob PortmanRepublican opposition to raising the minimum wage Is crumbling Trump: 'Very disappointed' GOP senator dropped support GOP senator: I'd consider Clinton Supreme Court pick MORE
(R-Ohio), came out in support of same-sex marriage ahead of the Supreme Court arguments. But Portman, who has a gay son, remains the only Republican in the Senate who backs gay marriage. Other top contenders for the Republican presidential nomination, including Sens. Marco RubioMarco RubioNew York Times endorses Rubio's rival Rubio: GOP Congress could go in different direction than Trump Poll: Clinton holds 4-point lead in Florida MORE
(R-Fla.) and Rand PaulRand PaulWhat the 'Bernie Sanders wing of the GOP' can teach Congress GOP senators avoid Trump questions on rigged election How low is the bar for presidential candidates, anyway? MORE
(R-Ky.), have recently voiced their opposition to allowing gays to wed.
The Republican opposition comes despite an apparent shift in national attitudes on the subject. A CBS News poll released earlier this week showed that 53 percent of all Americans believe it should be legal for same-sex couples to wed, although 56 percent of Republicans do not support allowing gay couples to do so. Still, GOP support has risen 13 percentage points since May 2012, when President Obama announced his support of same-sex marriage.