While you might think it’s impossible to put a scientific number on how liberal or conservative a United States Representative or Senator is, the folks at Vote View have been doing that for years. The website was established in 1995 and the purpose was to publish the data resulting from the research of political science professors Howard Rosenthal and Keith Poole.

Although I won’t cite the list all 3,320 Presidents, House and Senate members in the survey, a complete listing can be found in a 2004 article by Keith Poole: Is John Kerry a Liberal? Scrolling through the scores, you might find it interesting to find out that Sonny Bono had a more conservative voting record than Newt Gingrich or Rick Santorum. You might also find it interesting that there is one presidential candidate, who is currently in second place in delegate count as of this date, who was by far the most conservative representative over a 65 year period in American history — and arguably the most conservative congressman of all time.

Here is the explanation of the data.

Below is a listing from left to right of all 3,320 individuals who served in either or both the House and the Senate from 1937 to 2002. Senator Kerry is number 478 and President Bush is number 2,971. The Common Space Score is the number in the furthest right column. (These scores are very highly correlated with the corresponding DW-NOMINATE Scores by Chamber.) Note that the Presidents are also shown in the coordinates below. Their coordinates are based upon Presidential Support Roll Calls compiled by Congressional Quarterly. These are typically a fraction of the total roll calls cast so the Presidential scores are very noisy compared to the members of Congress.