Prime Minister Mark Carney says he studied the possibility of U.S.-led military action in Canada. In a lengthy New York Times interview published Wednesday, Carney declined to discuss in detail what that examination involved, but he suggested it would be irresponsible not to prepare for what he called "extreme tail risk." "I think you have a responsibility in these roles to look at extreme tail risk," Carney told the Times. "That's just risk management. That's not a base case, but it would be irresponsible not to [prepare]." U.S. President Donald Trump has repeatedly mused about turning Canada into the 51st...