(CNN) About a third of Americans say blackface is sometimes OK for a Halloween costume, according to a Pew Research Center poll that reveals divides on the issue among political lines.

Wearing blackface is always acceptable for Halloween, 15% of respondents say, while another 19% said it's sometimes acceptable.

The survey was conducted mostly before recent controversies over blackface roiled politics in Virginia, where the governor and attorney general both admitted to darkening their skin as part of costumes. And there's a long line of politicians and celebrities who've gotten flack for wearing blackface.

The issue has sparked debate since it was discovered that Virginia Gov. Ralph Northam's medical school yearbook featured a picture of a man in blackface next to a person in a KKK outfit. Northam also admitted to wearing blackface to a party. Separately, the state's attorney general, Mark Herring, also a Democrat, admitted to wearing blackface to a party in college.

Now, according to Pew, barely more than a slight majority -- 53% -- of all American adults think its unacceptable for a white person to use blackface in a costume.

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