Over the years, Bill and Nadia Lockyer's neighbors watched the couple walk their young son up and down their Hayward street at Christmastime, admiring the festive lights. The image of this political power couple seemed as perfect as a campaign commercial. Everything seemed "hunky-dory" between the 70-year-old state treasurer and the 40-year-old Alameda County supervisor, said neighbor Stephen Welch. "He seemed happy. She seemed happy. I've never seen conflict or strife or anything," he said. But this week, after stories emerged of Nadia Lockyer's substance abuse, extramarital affair and alleged beating by a former lover in a Newark motel room,...