Canada's new Prime Minister Mark Carney has asked Defense Minister Bill Blair to review the purchase of America’s F-35 fighter jet to see if there are other options “given the changing environment," a spokesman for Blair said Saturday.

The former central bank chief takes over at what he has called “a time of great peril” for Canada, with Trump attacking its sovereignty and economic security.

But, at the same time, no option is off the table—including restrictions on energy and natural resources. Because of the highly-linked energy systems of the two countries, such a move could wreak significant havoc on the U.