Newfound Republican favor is likely driving the overall increase — Gallup reports a record 55 percent of GOP voters now find themselves on the same side of the issue as their Democratic counterparts, 83 percent of whom currently back same-sax marriage. The high level of support among Democrats has remained fairly consistent over the last few years.
Recent endorsement among older U.S. adults may have aided in the jump, as well. In 2021, 72 percent of middle-aged adults and 60 percent of older adults say they now believe in the legal recognition of same-sex marriage, up 10 percent and 9 percent from 2019, respectively.
As part of its annual Values and Beliefs poll, Gallup surveyed 1,016 adults from May 3-18, 2021. Results have a margin of error of four percentage points. See full results at Gallup.