Today, President Obama announced he supports gay marriage. The president revealed his position in a much-anticipated interview with ABC. Previously, the president had claimed that his stance was “evolving.” There weren’t many people who actually believed him—the notion that his views were shifting a little bit every day was always kind of ridiculous—but the politics of the issue are dicey, and campaign season is a risky time to announce a major policy shift. But leaving aside for a minute the president’s personal evolution, how has the American public evolved on this and other controversial cultural issues?

A 2011 study shows that, on most cultural issues, the American people have become progressively more liberal in recent decades. Analyzing public opinion trends from 1972 to 2010, the authors found that in that time span, Americans’ cultural policy “mood,” on most of 16 surveyed issues, “has moved steadily and consistently in a liberal direction.” These changes in cultural policy mood are “not associated with changes in aggregate opinions about race or government spending,” but they “have been tightly linked to changes in aggregate religiosity.” The outliers are the death penalty and abortion—on the former, opinion has oscillated, and on the latter, public views have become more conservative over time. And as for the future? Predictions will make fools of us all, but something tells me the president’s announcement today shows that he knows which way the trend on gay rights is moving—and he may finally be ready to do his part to accelerate it.