At CNN, when is a “clear” lead a “slight edge”?

Heading into today’s Indiana primary, CNN reports that Hillary Clinton has “a clear lead” — 48 percent of polled Democrats prefer her, compared to 44 percent who say they’d vote for Barack Obama. While CNN doesn’t reveal their margin of error, it curiously notes another four-point lead, this time showing Obama ahead in national polls. This time around, that four-point advantage is characterized differently — as “a slight edge over Clinton.”

The news site reports that Obama leads Clinton by eight points in North Carolina, a state that’s also holding a primary today.

Update: Zogby’s newest poll shows Obama with a 14-point lead over Clinton in North Carolina (51-37) and a statistically insignificant two-point lead over Clinton in Indiana (45-43).