During the 2004 presidential election, Dick Cheney and other leading Republicans claimed -- falsely, as it turned out -- that the National Journal's analysis of 20 years of voting records had pegged John Kerry as the "most liberal" member of the Senate.

Here we go again.

In an e-mail distributed to reporters this morning, the Republican National Committee's Research Department says that Barack Obama -- and not Dennis Kucinich -- is the "most liberal member of Congress" currently running for the presidency. The RNC cites a McClatchy Newspapers report which relies, in turn, on the most recent "lifetime" scores from the National Journal.

Sort of.

The problem? To come up with its annual and lifetime rankings, the National Journal compares senators' voting records to other senators' voting records and House members' voting records to other House members' voting records. The resulting "liberal scores" and "conservative scores" are percentiles.

Thus, Obama's "lifetime liberal score" of 84.3 means only that, by the National Journal's math, Obama's Senate voting record makes him more liberal than 84.3 percent of senators. And Kucinich's "lifetime liberal score" of 79.4 means only that Kucinich is more liberal than 79.4 percent of House members. As the National Journal's Richard Cohen confirmed for us in a telephone call this morning, you can't do an apples-to-apples comparison of the two. And even if you could, the difference between an 84.3 and a 79.4 would be less than meaningless given (1) Obama's short tenure in the Senate, (2) Kucinich's evolution from center to left over the years, and (3) the sheer number of farther-left liberals in the House.