Canada has a trade war on its hands -- and it is one entirely of its own making. For the past four months, two of its western provinces, Alberta and British Columbia, have been exchanging blows over an expansion to Kinder Morgan's Trans Mountain pipeline, which transports diluted bitumen from Edmonton, Alberta, to Burnaby, British Columbia. On April 16, the Alberta government introduced the Preserving Canada's Economic Prosperity Act, which would give Edmonton the power to cut off all crude oil, natural gas and refined product exports to its neighbor. That move could force British Columbians to pay about 30 percent more for gasoline, among other secondary effects. The willingness of Alberta Premier Rachel Notley to attempt such extreme measures to protect her province's greatest resource highlights the significance of the spat to both provinces -- and to the rest of Canada, and even the United States....