This morning, there was a stunning development in Congress’s investigation of the Justice Department’s “Fast and Furious” gun-running program: it was revealed that on July 4, Kenneth Melson, the acting director of the Bureau of Alcohol, Tobacco and Firearms and the Obama administration’s intended fall guy in the scandal, broke ranks with his superiors. Without their knowledge, he gave an interview to Darrell Issa’s House Committee on Oversight and Government Reform, accompanied only by his personal attorney. While a transcript of that interview is not yet public, it is clear that he blew the whistle on senior officials in the...