Ottawa:  Canada has not changed its position on not joining the U.S. missile defense shield, but said it is continuing to examine its stance given changing global circumstances.

Speaking in Brussels at the end of a meeting of the Group of Seven leading industrialized nations, which was dominated by how to tackle Russian moves in Ukraine, Harper said Canada regularly examined policies, including the missile shield.

“It was our judgment in the past that Canadians did not need the security of participation in the anti-ballistic missile defense system,” the Conservative prime minister said.

“Obviously there are changes occurring in the world and we will continue to examine whether that does or does not serve Canadian interests and we’ll make whatever decisions are in the best security safety interests of Canadians, but obviously at the moment we have not decided to revise the position.”

The previous Liberal government had decided in 2005 under Prime Minister Paul Martin against joining the shield, at a time when then-U.S. President George W. Bush was not popular within the Canadian government.

But two former Liberal defense ministers, Bill Graham and David Pratt, urged the Conservative government, in Senate committee last month, to join the program.

Part of Canada’s calculation in not investing in the defense shield has been that with its main cities close to the U.S. border, it would already be effectively covered to a large extent.

The thinking went that missiles heading in the general direction of Vancouver, British Columbia, for example, would likely be targeted anyway by U.S. defenses protecting Seattle, Washington, just 120 miles (193 km) to the south.

The system is still in the process of being tested and improved on, and is not yet fail-safe, but advocates say it is important to try to defend against possible threats from countries like North Korea and Russia.