NEW YORK (AP) — Facebook is under fire for failing to rein in fake and biased news stories that some believe may have swayed the presidential election. Its predicament stems from this basic conundrum: It exercises great control over the news its users see, but it declines to assume the editorial responsibility that traditional publishers do.

On Monday, Facebook took a minor step to address the issue, clarifying its advertising policy to emphasize that it won't display ads on sites that run information that is "illegal, misleading or deceptive, which includes fake news." The company said it was...