The admirable Mr. Taranto at the Wall Street Journal writes about this frequently, but Newsbusters actually produced numbers on how often politicians caught in scandals have their party identified. As you might have guessed, scandal-ensnared Republicans are usually identified; scandalous Democrats suddenly become nonpartisan independents:

My colleague Brent Baker has painstakingly documented how the big three broadcast networks have gone out of their way to avoid labeling scandal-scarred New York Governor Eliot Spitzer as a “Democrat.” An examination of the fifteen ABC, CBS and NBC morning and evening news shows through Wednesday night finds Spitzer was called a Democrat just 20% of the time — twice on CBS, once on ABC, and never on NBC. So how do the networks treat Republicans involved in sex scandals? Always, always as Republicans, and as problems for their party. Last July, Louisiana Senator David Vitter’s name surfaced in the phone records of the “DC Madam,” Deborah Jean Palfrey. Over the next week, ABC talked about Vitter twice on World News and twice on Good Morning America, labeling him as a “Republican” or “conservative Republican” all four times. The CBS Early Show aired two Vitter stories, and both times called him a Republican. For some reason, the CBS Evening News did not report on Vitter that week. NBC’s Today mentioned Vitter on two different mornings, and called him a Republican both times. The NBC Nightly News reported on Vitter once, and called him a Republican.

I had an anecdotal impression that this was probably the case, but I had always doubted the validity of that impression, since I spend so much time looking for media bias. You find what you’re looking for–that’s how media gets biased in the first place. Thinking about how to to counteract one’s own bias when writing about media bias (so as not to produced biased media reports about media bias) has the potential to send me off on one of those head-clutching David Foster Wallace/Douglas Hofstadter infinitely self-referential loops, so I’m glad to have a little data to anchor the discussion.