Over all, the vast majority of Americans say they do not believe the United States has a responsibility to intervene in the Syrian conflict, which has killed more than 90,000 people over more than two years. On average, only about one in four Americans say the United States has an obligation to intervene.

Polls that have asked whether the United States ought to get involved in Syria — rather than whether the United States simply has the responsibility to — have found similar numbers: A Gallup poll from late May found that 24 percent supported intervention. Just 17 percent supported intervention in a survey conducted in December by ABC News and The Washington Post. …

According to an average of the three surveys in the PollingReport.com database that asked, 58 percent of adults said they would support military intervention if it were confirmed that the Assad regime had used chemical weapons either on antigovernment forces or on civilians. (It remains to be seen, of course, whether public support for military intervention will actually increase now that such a confirmation has come.)