"I think we still have to do litigation, we still have to do legislation, but we also have to do education as well," said Mathew Staver, founder and chairman of the Christian legal group Liberty Counsel.
Since same-sex marriages began in Massachusetts in 2004, approximately 100,000 gay couples have gotten married across the U.S., said Lee Badgett, a professor of economics at the University of Massachusetts-Amherst. At least 16,000 of the marriages have taken place in Massachusetts.
Evan Wolfson, founder and president of Freedom to Marry, said 38 percent of Americans will live in states where same-sex marriage is legal once Illinois's governor signs the bill on Wednesday. The group has a goal of bringing that up to more than 50 percent by the end of 2016.
"What we have to do — like other civil rights movements and social justice causes — is win a critical mass of states and a critical mass of public support, which together creates the climate for the Supreme Court to bring the country to national resolution," Wolfson said.
Wolfson said Oregon is expected to be a key battleground in 2014 as supporters hope to repeal a constitutional ban on gay marriage passed in 2004 during a rush of similar amendments in other states after the Massachusetts' ruling.
But Staver said he believes the momentum of the gay marriage movement will slow.
"Same-sex marriage represents a classic conflict with religious freedom," he said. "I think there will come a tipping point where the pendulum will swing the other way as people begin to see the impact of same-sex marriage."