Michigan’s demand that Enbridge close its 68-year-old oil pipeline (Line 5) across the Straits of Mackinac joining lakes Michigan and Huron did not come out of nowhere. It is essentially the fifth “wave” of opposition to Canadian oil pipelines that suddenly erupted in 2010. The first four cases, of course, were TransCanada’s Keystone XL pipeline, then Enbridge’s Northern Gateway pipeline, followed by TransCanada’s Energy East pipeline and Kinder Morgan’s TransMountain Expansion pipeline.