NEW YORK — Before the United Nations can save the planet, it needs to clean up its own house. And as scandal after scandal has unfolded over the past decade, from Oil for Food to procurement fraud to peacekeeper rape, the size of that job has become stunningly clear. But any understanding of the real efforts that job entails should begin with a look at the long and murky career of Maurice Strong, the man who may have had the most to do with what the U.N. has become today, and still sparks controversy even after he claims to have...