By John Solomon
How the government's punishing of the exposure of official wrongdoing can linger for years

U.S. Attorney Ronald C. Machen Jr. followed a public shaming of the former D.C. Council chairman this week with a vow to "ensure public trust" — a pledge sure to be tested as he resolves his probe into Mayor Vincent C. Gray's 2010 campaign, the last in a trio of investigations that blazed a path this year from city hall to the federal courthouse.