When Connecticut Attorney General Richard Blumenthal, a liberal Democrat, decided to sue the federal government over testing provisions in the No Child Left Behind Act, he probably wasn't expecting flak from his political left. But that's exactly what he's received since filing the lawsuit last week. As first reported in the Hartford Courant, two national civil rights leaders, William Taylor and John Brittain, fired a letter to Mr. Blumenthal calling the lawsuit "ill-advised" and disputing his claim that the federal law is "an unfunded mandate." Messrs. Taylor and Brittain run civil rights organizations based in Washington but are veterans of...