A memo to reporters on climate science suggests an unacceptable level of bias.

4:12 PM PST, December 17, 2010

Love it or hate it, Fox News has shaken up the media establishment and achieved financial success by airing the views of strident conservative pundits. Yet while the network has never made any bones about the political slant of opinion shows hosted by the likes of Glenn Beck, Sean Hannity or Bill O'Reilly, executives often claim that its news coverage is "fair and balanced." A memo revealed this week by the liberal watchdog group Media Matters calls that into question.

The first time Media Matters unveiled a leaked e-mail from Bill Sammon, Fox News' Washington managing editor, it was hardly worthy of mention. On Dec. 9 the group's website revealed that Sammon had instructed reporters to avoid the phrase "public option" when referring to a proposed government-sponsored healthcare plan. The memo, sent out on Oct. 27, 2009, when debate over the Democratic healthcare bill was raging in Congress, came two months after Republican pollster Frank Luntz had appeared on Hannity's show and encouraged him to use the phrase "government option" instead, because such terminology decreased public support for the proposal. "Please use the term 'government-run health insurance' or, when brevity is a concern, 'government option' whenever possible," Sammon told reporters.

Liberal bloggers were furious, but few mainstream journalists could muster much outrage. Arguments over semantics and perceived bias are commonplace and seldom fruitful. "Government option" is no less valid a descriptor for the proposal than the more commonly used "public option," and if Fox News was demonstrating bias by using the former, one could accuse mainstream outlets of the same for using the latter.

But a second intercepted missive from Sammon is quite a bit more troubling.

"We should refrain from asserting that the planet has warmed (or cooled) in any given period without IMMEDIATELY pointing out that such theories are based upon data that critics have called into question," read an e-mail sent by Sammon to news reporters on Dec. 8, 2009, and revealed this week by Media Matters. The memo went out 15 minutes after a Fox News reporter accurately explained to viewers that United Nations scientists had issued a report saying 2000 to 2009 was shaping up to be the warmest decade on record — even warmer than the 1990s, which were warmer than the 1980s.

Such data aren't in serious dispute among climate scientists. The way the data are interpreted can vary; it's legitimate for climate skeptics to reach conclusions that contradict mainstream theories. But only a crank would deny the underlying temperature data that show the Earth getting warmer — records compiled by independent stations around the world, combined with satellite measurements and confirmed by observations of rising sea levels, vanishing glaciers and other inputs — because to do so is to deny material and measurable facts. Instructing reporters to treat such facts as controversial is like telling them to question the laws of gravity when discussing plane crashes. The only reason for doing it is to further a partisan agenda, in this case an attempt to cast doubt on climate science in order to fend off government efforts to limit greenhouse gases.

Fox should either come clean about this and crack down on such partisanship in its news ranks, or it should stop pretending to be an objective news source.