Congressman extols the virtues of abstinence in a video shot with his mistress. Go figure.

First there was former Sen. John Edwards. Now it’s Rep. Mark Souder. What is it about politicians that compels them to post videos involving their sexual partners? The part-time staffer who reportedly had an affair with Souder, an Indiana Republican, conducted video interviews with her boss while they were romantically involved. Souder, who is married and has served eight terms in the House, unexpectedly resigned at a press conference on Tuesday. The staffer has been identified as Tracy Jackson. A five-m…