Friday on CNN's American Morning, network correspondent Alina Cho conducted a "reality check" of a John McCain ad that labels Barack Obama the most liberal member of the U.S. Senate.  These "fact checks" are increasingly popular in the mainstream media this presidential year.  Cho started:

ALINA CHO, CNN, CORRESPONDENT: Good morning. And a whole team of researchers, John, the truth squad as you're calling it, and we're starting today with a charge that the McCain campaign has been making against Barack Obama's voting record. Out on the campaign trail, John McCain has been calling Obama's record the most liberal in the Senate. Many people have heard that. The charge was also leveled early this month at an ad comparing Sarah Palin to Obama. Take a listen.

(BEGIN VIDEO CLIP)

UNIDENTIFIED MALE: The "Journal" says Governor Palin's credentials as an agent of reform exceed Barack Obama's. They are right.

UNIDENTIFIED FEMALE: He has a record of bipartisan reform.

UNIDENTIFIED MALE: He's the Senate's most liberal.

UNIDENTIFIED FEMALE: She took on oil producers.

UNIDENTIFIED MALE: He gave big oil billions in subsidies in giveaways.

UNIDENTIFIED FEMALE: She's earned a reputation as a reformer.

UNIDENTIFIED MALE: His reputation, empty words.

SEN. JOHN MCCAIN (R), PRESIDENTIAL CANDIDATE: I'm John McCain and I approve this message.

(END VIDEO CLIP)

CHO: Well there's the ad. Here's the reality check. The "National Journal Magazine" which bills itself as a non-partisan publication did report recently that Obama moved so far to the left last year that he did rank the most liberal senator after ranking 16th and 10th most liberal in his first two years in the Senate.

But the Americans for Democratic Action, a liberal activist group disagrees.  No surprise there.  The group says when you look at Obama's entire Senate voting record, Hillary Clinton, John Kerry and Ted Kennedy actually have higher liberal ratings.  So is Obama the most liberal senator? The verdict, true, according to the "National Journal." But this is the only source we could find. Other groups say liberal but not the most liberal.

So, John as you can see, not always black and white and this is where the campaigns seize on it and use to it their advantage as you well know after covering politics for a very long time.

Using the words "not always black and white" may steer viewers to conclude that the McCain ad is less than accurate.  Cho's declaration on the ad's veracity: "The verdict, true, according to the 'National Journal.'  But this is the only source we could find" is misleading.  The only source cited in the McCain ad was the National Journal, with a shot of the Web page designating Obama the most liberal senator in 2007 and the words "most liberal" captioned below it.

Cho states that that Americans for Democratic Action says other senators have higher career liberal ratings.  That may be true, but the McCain ad didn't speak in terms of lifetime voting records.  Moreover, the reason for Obama's receiving a relatively low 75 percent rating from the ADA for 2007 is because he missed votes, probably because of campaigning.  On every single measure on which he did vote, Obama embraced the liberal ADA position.

So where does "not always black and white" fit in?  Clearly it doesn't apply to the McCain ad Cho did a "reality check" on.

And noting that the National Journal "bills itself as a non-partisan publication," is a nice touch from CNN, which, as has been reported multiple times on NewsBusters, identifies some obviously partisan organizations as non-partisan merely because they "bill" themselves that way.

This isn't the first media report - nor will it be the last - that suggests a McCain ad is less than correct.  That may well be right in some instances, but it's worth our time to fact check the fact checkers before buying into their findings.