A new Public Policy Poll finds a substantial increase in support for gay marriage among African-Americans in Maryland.  How should we interpret this?  Glenn Greenwald and Adam Serwer think it’s evidence that presidential leadership can move public opinion.  Brendan Nyhan notes that public opinion nationally hasn’t really moved—citing Lynn Vavreck and Ryan Enos’s analysis as well as a new Washington Post poll.  Jon Bernstein isn’t sure that it’s the president’s leadership:

So it’s not exactly that Obama influenced black opinions, would be my guess. It’s that African American voters who really don’t care very much one way or another about the marriage issue — but do consider themselves on Team Democrat — are now aware that marriage equality is the normal position of that team. Or, perhaps, that those who think of themselves (implicitly or explicitly) as Team Black now have a revised view of what that team’s position is. Or, perhaps, people who are on Team Church and Team Democrat now realize that those two are in conflict and they have to choose, while before they were getting only one signal.

Although the polling data thus far generally support the finding that presidents don’t move public opinion very much or very often, there is some reason to believe that Obama himself could move opinion among African-Americans.  In a 1994 paper (gated), James Kuklinski and Norman Hurley conducted an experiment in which respondents read a statement urging African-Americans to demonstrate more self-reliance.  The statement was attributed to Jesse Jackson, Clarence Thomas, George Bush, Ted Kennedy, or no one.

Among black participants, the most persuasive cue-giver was Jackson, following closely by…?  Thomas.  Kuklinski and Hurley write that:

…subjects deem the race of the political leader, not his ideological reputation, to be the relevant contextual information. Consequently, two political figures as ideologically opposite as Jackson and Thomas can equally “inform” people as to the “right” stance to take on the issue of black self-reliance.

This is nothing unique to Jackson or Thomas or even African-Americans, of course.  Sources of information are generally more credible when they are perceived as sharing our identities, values, etc.

Because Obama is still very popular among African-Americans and because his shift on same-sex marriage was publicized widely, some blacks could plausibly take a cue from him and change their positions.  Maybe, as Jon suggests, many of them didn’t actually have strong opinions to begin with.  But Obama could still have been the catalyst for their own shifts in opinion.

Two caveats, however.  First, it would be nice to have more polls to back this up.  Second, Obama’s potential leadership in this case doesn’t suggest presidents have broad persuasive powers.  If Obama’s endorsement of same-sex marriage did shift the views of some African-Americans, that is still a shift among only a minority of a minority of voters in, as far as we know, a single state.

[Update: The Washington Post polling unit reminds me that their national poll also showed a shift among African-Americans, a finding they characterize as “tentative” but that nevertheless supports the PPP results from Maryland.]

[Cross-posted at The Monkey Cage]

John Sides

John Sides is an associate professor of political science at George Washington University.