"For proponents of marriage equality, years of playing offense have finally paid off as this movement has reached a tipping point in recent years - both legally and in the court of public opinion," said Justin McCarthy, a Gallup analyst. "Gay marriage supporters' game strategy has officially pivoted to challenging state bans in court."
When Gallup asked Americans if they supported same-sex marriage in 1996, 68 percent were opposed. Now that figure has decreased to 42 percent. However, gay marriage support has continued to rise since 2011 when the issue gained majority support for the first time.
The study found that support is highest among young adults, with 78 percent of those under 30 saying they approve, and Democrats, 74 percent of whom say they are on board. However, only 30 percent of Republicans think it should be legal and a majority of those older than 50 also oppose it.
McCarthy believes young Americans will likely continue to drive overall support at a consistent pace just like they have in recent years.
The survey also found that the South is about evenly split on gay marriage, with 48 percent of Americans there saying marriage should be legal. But McCarthy notes that Southern states, most of which have constitutional bans on same-sex marriages, are the new target region for gay advocates.
"While the map of gay marriage is regionally diverse, it is not so in the South, where traditional marriage advocates still hold a majority of support. Public opinion in Southern states will be a barometer to observe, as the bulk of future legal battles will play out there in the months and years to come," McCarthy said.
Arkansas saw the legalization of gay marriages into the Bible Belt earlier this month but the state's Supreme Court suspended the ruling and halted the distribution of marriage licenses a week after a judge overturned the state's gay marriage ban.
Gallup's findings also come amid a slew of recent victories for gay rights advocates after two federal judges struck down bans on same-sex marriage this week in Oregon and Pennsylvania.
The May 8-11 poll of 1,028 American adults has a margin of error of plus or minus five percentage points.