Every year, the National Journal, a Washington weekly magazine, comes out with a ranking of the most liberal and conservative members of Congress. And just about as often, political campaigns use those rankings to score points against their opponents. But looking at the start of this year's list (the Journal released only partial results; the full list will be out in March), we can't help thinking of that other big annual ranking, U.S. News & World Report's college list. And we can't help wondering whether the National Journal's list is just as capricious -- and even, dare we say it, inaccurate -- as that one.

That's because the big finding the Journal is trumpeting this time around is that the Senate's most liberal member in 2007 was Sen. Barack Obama. That puts him ahead of, for example, Wisconsin Sen. Russ Feingold. Oh, and it also puts him ahead of an actual socialist, Vermont Sen. Bernie Sanders. And then there's the man at No. 3, Delaware Sen. Joe Biden, hardly known as a raging lefty. Biden comes in ahead of both Feingold and Sanders as well. (Sen. John Kerry was ranked as the most liberal in 2003, another distinction that seems dubious and became a campaign issue.)

If you're wondering, Obama's rival for the Democratic presidential nomination, Sen. Hillary Clinton, is ranked 16th. That raises another question: Just how far apart are Obama and Clinton, really? The article the National Journal printed explaining its results suggests that, despite the disparity in their rankings, Obama's and Clinton's records were not that different for 2007. "In their yearlong race for the Democratic presidential nomination, Obama and Clinton have had strikingly similar voting records. Of the 267 measures on which both senators cast votes in 2007, the two differed on only 10," the authors write before going on to quote Richard Lau, a Rutgers University political scientist, as saying, "The policy differences between Clinton and Obama are so slight they are almost nonexistent to the average voter." The Journal qualifies these caveats by saying, "In a Senate in which party-line votes are the rule, the rare exceptions help to show how two senators who seemed like ideological twins in 2007 were not actually identical. Obama and Clinton were more like fraternal policy twins."

In an interview with War Room, National Journal editor Charles Green defended his magazine's analysis. "It varies from year to year who is listed as most liberal. It's rarely the same person every year ... there's some fluctuation," Green said, noting that moderate to conservative Democrats rarely end up ranked as liberal and that conservative Republicans also end up in the conservative column. As for the question of the difference between Obama and Clinton, Green said, "Are they two peas in a pod because they voted the same on 257 out of 267? Perhaps to some people, but to other people those other 10 votes where they differed help explain some of their positions."

On the Republican side, there are two remaining presidential candidates who are also members of Congress, Arizona Sen. John McCain and Texas Rep. Ron Paul. McCain missed too many votes to be included in the rankings; Paul ranked as the 178th most conservative member of the House of Representatives for the year.