Canada invokes treaty with US in push to keep cross-border pipeline open

Canada warns of significant' economic damage in the event of a shutdown of Line 5, which travels through Michigan

Canada has once again invoked a longstanding treaty with the US as it seeks to keep a controversial cross-border pipeline open, warning of significant" economic damage to both countries in the event of a shutdown.

Canada's foreign minister said Line 5, a pipeline operated by Calgary-based Enbridge, was a critical source of energy security.