Whenever a Democratic Senator runs for president, National Journal comes along with a deeply flawed scheme purporting to rank members of congress. In both 2004 and 2008, National Journal just happened to announce that a frontrunner for the Democratic presidential nomination was the "most liberal" member of the Senate. In order to call Barack Obama the "most liberal" in 2008, National Journal changed the system they had previously used. Nothing suspicious there!
Worse, National Journal's PR operation then sent out promotional materials hyping the findings by touting the impact the 2004 rankings had on that year's presidential campaign -- conveniently ignoring the fact that, according to National Journal itself, the system used to declare John Kerry the "most liberal" Senator in 2004 was flawed.
And it's pretty obvious what happens next: Republicans start shouting the results from the rooftops, and the media eat it up with a spoon.
The important thing to know about the National Journal ratings -- the only important thing to know about them -- is that they are pretty much worthless. A 2007 vote in favor of implementing the 9/11 Commission's recommendations, for example, was counted as a "liberal" vote. Norman Ornstein of the American Enterprise Institute -- certainly nobody's idea of a liberal -- called NJ's ranking "pretty ridiculous."
National Journal's just-released new rankings should remove any lingering suspicion that they might have some validity. That's because the magazine has concluded that Dennis Kucinich is the 160th most liberal member of the House of Representatives. 160! Kucinich's rating is presumably a result of votes he cast against legislation that he didn't think was liberal enough -- among NJ's "key votes" is the passage of the House health care bill, which Kucinich voted against.
So, basically: National Journal vote ratings should not be taken seriously. Unless you think Dennis Kucinich is really the 160 most liberal member of Congress and that opposing legislation from the left makes you less liberal and that implementing the 9/11 Commission's recommendations makes you liberal.
If media absolutely must refer to ideological rankings of members of Congress*, they would do well to take a look at the rank ordering done by political scientists Jeff Lewis & Keith Poole. Unlike National Journal, they don't cherry-pick a handful of votes; they looked at 694 votes for their current House rankings. And they conclude that Kucinich had the 7th most liberal voting record in 2009.
That seems a bit more reasonable than National Journal's rankings, doesn't it?
* Which, weirdly, they only seem to want to do when discussing Democrats. Maybe because if they actually looked at reasonable ranking systems, they wouldn't be able to call Lindsey Graham a "moderate."