Two front-page stories about our national political climate in the March 4 Maine Sunday Telegram caught my attention.

The first noted that the congressional “center has eroded over time.” My own analysis of the numbers you published supports this conclusion. Members of the House and the Senate are abandoning the political center.

The proportion of centrist senators declined from 10.8 percent in 1979-80 to 5.8 percent in 1995-96 to 2.9 percent in 2009-10. The House’s abandonment of the center has been more dramatic, dropping from 11.5 percent centrists in 1979-80 to 6.1 percent in 1993-94 to 1.9 percent in 2009-10.

The other story carried the headline: “Analysis shows Congress shifting toward extremes.” This conclusion may seem to follow logically from the first, but this story’s headline is not supported by the data.

An ideological shift has been going on in both houses, but it is primarily in one direction – toward the right – and it is more pronounced in the House than in the Senate. The proportion of conservative House members scoring 5 and above (the most extreme) rose from 4.4 percent in 1979-80 to 8.2 percent in 1993-94 and to 18.2 percent in 2009-10. Among liberal members, the proportion scoring 5 and above remained fairly stable, going from 11 percent in 1979-80 to 13.8 percent in 1993-94 then back to 13.3 percent in 2009-10.

In other words, Democrats at the ideological extreme more or less maintained their proportion over time, whereas the Republican delegation became much more conservative. Examination of other groups – those scoring 1-2 and 3-4 on the published scale – show that both parties have drifted to the right.

A more accurate headline would have been “Republicans move to the extreme as Congress becomes more conservative.”