In a June 30 Time article, Washington bureau chief James Carney wrote: “As any Republican will tell you, the National Journal ranked [Sen. Barack] Obama the most liberal member of the Senate.” But what Carney did not tell his readers was that the National Journal's rankings are based on subjective criteria. Indeed, the National Journal's 2007 Vote Ratings were based not on all votes cast by senators in 2007, but on "99 key Senate votes, selected by NJ reporters and editors, to place every senator on a liberal-to-conservative scale." In contrast, a study by political science professors Keith Poole and Jeff Lewis, using every non-unanimous vote cast in the Senate in 2007 to determine relative ideology, placed Obama in a tie for the ranking of 10th most liberal senator. Media Matters for America has repeatedly documented instances in which media figures have cited the National Journal ratings without noting their subjectivity.

In a June 16 PolitiFact.com article analyzing the Journal ratings, St. Petersburg Times Washington bureau chief and PolitiFact editor Bill Adair reported that National Journal editor Charles Green “says voters shouldn't rely on a single rating to determine a candidate's ideology” and quoted Green as saying, “There's pluses and minuses to each rating system. If you look at a number of them, I think you have a pretty good picture.” Additionally, American Enterprise Institute resident scholar Norman J. Ornstein has also criticized the National Journal's rating of Obama as the “most liberal senator” in 2007, calling it “pretty ridiculous.”

From Carney's June 30 Time article, “The Week in Politics”:

As Obama assumed the role of front-runner, the press this week began to take note, in some cases disapprovingly, of the presumptive Democratic nominee's efforts to shuffle to the political center. As any Republican will tell you, the National Journal ranked Obama the most liberal member of the Senate. And in the primaries Obama took routinely liberal positions on all the major issues of the day. But in tone as well as in substance, Obama has started making the traditional general election move to the middle. His first television spot of the general election was biographical, focusing on his love of family and country, and highlighting his legislative efforts “to move people from welfare to work” and “cut taxes.” Much to the dismay of many liberals, Obama supported the bipartisan compromise worked out this week on so-called FISA legislation that allows the Bush Administration to continue its wiretapping program. Obama was also conspicuously centrist, even conservative, in his reaction to two major Supreme Court rulings this week - the first disallowing the death penalty in cases of child rape, and the second affirming that the Second Amendment guarantees individuals the right to own guns for self-defense. Obama criticized the first decision, saying he supports the death penalty for such a heinous crime; his response to the gun ruling was muddled, but it made clear that he supports an individual's right to own a gun.