Of all the issues ripe for further investigation in the scandal over the leak of Democratic strategy memos from the Senate Judiciary Committee last year, the least relevant is whether GOP staffers "stole" the documents. That's the charge Democrats have so far successfully made to deflect attention from the memos' actual content. On this point alone, the Justice Department's decision this week to open a criminal investigation into the matter could turn out to be useful. David Kelley, the U.S. Attorney in Manhattan, and a Democrat, has been tapped to lead the probe. We doubt Mr. Kelley is going to...