It appears crimes have long shadows, at least several years in some cases. Seandell Jackson killed Nathan Potter in Milwaukee in 2009. Jackson was a convicted felon who had shot someone a few hours before he shot Potter. For the same reason: Of course it was a robbery, but he told the judge he thought he was “having fun.” Potter was college student at the University of Wisconsin-Milwaukee. By all accounts a gentle soul. A free spirit. A few hours before Potter’s execution, at least one person dialed 911 to report a couple of sketchy characters lurking around the neighborhood....