TORONTO—The dispute between Donald Trump and Justin Trudeau over Canada’s financial contribution to NATO is a sideshow. The real story is that Canada is being drawn increasingly into America’s wars. That is the import of Trudeau’s announcement last week on Iraq. Canada is already training Iraqi troops in the north of the country, as well as working in an unspecified manner with Kurdish militias there. Wednesday’s announcement commits Ottawa to running a new NATO training mission in Baghdad.