Who runs for Congress? Political scientist John Sides discusses a fascinating new paper by Duke’s Nicholas Carnes, who finds that, since 1901, the House has been dominated by business people, lawyers, and other private-sector and service professionals. Just a tiny fraction of Congress comes out of the working class. And that matters because a politician’s occupational background tends to be a fairly good predictor of his or her political attitudes. Here’s the chart:

By the way, note that the phenomenon of career politicians springs up relatively late in the game, really only blowing up in the 1980s. Alan Ehrenhalt’s 1991 book The United States of Ambition documented this cultural shift. Here’s an old interview with the author, in which he notes that career politicians first came in vogue within the Democratic Party, “the party that believes in government, isn’t embarrassed about it and is the natural vehicle for young people with talent who like politics and who want political careers.” Nowadays, however, it’s a staple of Washington.