Ottawa again invokes 1977 pipeline treaty in Line 5 dispute with U.S.

For the second time in a year, the federal government is invoking a little-known 1977 energy treaty between Canada and the United States to defend the Line 5 pipeline.

This time, it's in Wisconsin where Line 5 skirts the southwestern shores of Lake Superior before crossing into Michigan.

In both states, federal judges are hearing court cases aimed at getting the controversial cross-border pipeline shut down.

An Indigenous band in Wisconsin is arguing that the pipeline's owner, Calgary-based Enbridge Inc., no longer has the right to operate on its territory.

Foreign Affairs Minister Mlanie Joly said Canada is seeking treaty talks with the U.S. because of the importance of Line 5 to North America's energy security.

The treaty, which was invoked last October in the Michigan case, is expressly designed to ensure the uninterrupted operation of hydrocarbons through the U.S.

"The economic and energy disruption and damage to Canada and the U.S. from a Line 5 shutdown would be widespread and significant," Joly said in a statement.

"This would impact energy prices, such as propane for heating homes and the price of gas at the pump. At a time when global inflation is making it hard on families to make ends meet, these are unacceptable outcomes."

The statement says Canada "strongly" supports a proposal by Enbridge to reroute the pipeline around the Bad River Band reservation in northern Wisconsin.