The biggest threat

Greg Mankiw links to a Gallup poll reporting on what people believe is the biggest threat to the U.S. In 2006 55% of Democrats said that big government was, but in 2009 only 32% said the same. In contrast, in 2006 68% of Republicans said that big government was the biggest threat, while in 2009 it had risen to 80%. Independents did not show much change, with their numbers on big government as a threat dropping from 60% to 59%.

Is this an example of partisanship bias?

Update: Does this argue partisanship bias on the part of the press?