In this 1955 photo, freshman congressman John Dingell is sworn in by House Speaker Sam Rayburn, D-Texas.

Today’s editorial shines a spotlight on Congressman John Dingell , D-Mich., who’s made a career of blocking environmentally progressive legislation that leaves his auto-making constituents uneasy. One reader has already posted a response as a comment under Thursday’s “loose thread” invitation. Here’s a chance for others to get more mileage out of the topic.