“In just a few years in office, Sen. Obama has accumulated the most liberal voting record in the Senate.”

Using a well-proven strategy from the Republican playbook, Sen. John McCain has been asserting that Sen. Barack Obama is a liberal.

“In just a few years in office, Sen. Obama has accumulated the most liberal voting record in the Senate,” McCain said in a speech in New Orleans.

Republican candidates often brand their Democratic opponents as liberals to portray them as lefties who favor big government and high taxes. Linguists who study political rhetoric say Republicans have been so effective at giving the word a negative connotation that many Democrats won’t call themselves liberals. They prefer “progressives.”

Still, many political scientists and journalists use the term to represent the Democratic extreme of the political spectrum, and

National Journal,

a nonpartisan political magazine, uses a liberal-conservative scale for its annual rating of congressional votes.

The magazine’s editors and reporters choose key votes on major issues and those that they believe exhibit a split between liberals and conservatives and then calculate how often senators and House members vote each way. They calculate the liberal/conservative votes in three areas — economic, social issues and foreign policy — and then average them for a composite score. The annual rankings generate some publicity for the magazine, especially in election years. In 2004, the magazine said the most liberal senator was Sen. John Kerry, who became the Democratic nominee for president.

On Jan. 31, 2008, five days before the Super Tuesday primaries,

National Journal

published an article headlined “Obama: Most Liberal Senator in 2007.” The article said Obama had missed 33 of the 99 votes that were rated but that it was enough for a calculation. The magazine said McCain was not rated because he missed more than half the votes in the economic and foreign-policy categories.

Since Obama’s rating was announced, McCain and other Republicans have frequently cited it to criticize Obama. Rep. Dan Boren, a Democrat from Oklahoma, cited the rating last week in explaining why he was not supporting Obama.

Yet other ratings don’t show Obama as the Senate’s top lefty.

He wasn’t the top liberal in his two other years in the U.S. Senate according to

National Journal

. He was 10th-most liberal in 2006 and 16th in 2005.

The McCain campaign also cites a 2006 rating by the liberal group Americans for Democratic Action that gave Obama 95 percent, which the campaign noted was the same as Kerry and Sen. Barbara Boxer.

But there’s a little sleight of hand in that one. Although the McCain campaign is correct that Obama earned a 95 percent rating that year for voting the way ADA wanted, there were 10 senators who got more liberal scores than Obama, including Barbara Mikulski of Maryland and Richard Durbin of Illinois. (In the latest ADA rating, for 2007, Obama missed five of the 20 votes the group scored, so he received a 75 percent rating. But he voted the way ADA wanted on each of the 15 votes he attended.)

Voteview.com, a site created by political scientists that plots lawmakers on a liberal-conservative scale based on their voting patterns, calculated there were nine senators more liberal than Obama in the current Congress, including Russ Feingold of Wisconsin, Chris Dodd of Connecticut and Bernie Sanders of Vermont.

“Obama is a liberal, but he’s not the most liberal,” said Keith Poole, a University of California-San Diego professor who runs the site.

Ratings from

Congressional Quarterly

don’t measure liberal/conservative votes, but they show Obama is not quite as partisan as other senators.

In CQ’s calculation of party unity, which measures how often members vote with their party on bills where Republicans and Democrats split, Obama got a 97 percent rating last year. Ten Democrats had higher scores.

On votes where President Bush indicated his position, CQ found Obama supported the Republican president 40 percent of the time in 2007, which put Obama in the middle of the pack for Democrats. He supported Bush 49 percent the previous year.

If McCain had made a more general statement about Obama’s ideology, he could have been more accurate. But McCain’s statement that Obama “has accumulated the most liberal voting record” suggests it is a cumulative rating for all of Obama’s time in the Senate. But in fact, it is true for only

one

rating for

one

year. Measurements for other years and by other groups show Obama is not the No. 1 liberal — in some cases, far from No. 1. So we find McCain’s statement to be Barely True.

Editor’s note: This statement was rated Barely True when it was published. On July 27, 2011, we changed the name for the rating to Mostly False.