Calls for Canada to reverse former prime minister Paul Martin's decision not to join the anti-missile system have come pouring out of think tanks and newspaper editorial pages since North Korea tested a small nuclear bomb Oct. 9. The country has a few, unproven intercontinental missiles which could theoretically reach North America. So far, North Korea has not managed to build a nuclear weapon that could be mounted on a missile.

"I would like to see people talking to the government, but also talking to their own institutional church with letters to the bishops saying, 'Look, it's time we spoke up on this,' " said Barringer.

The Canadian Council of Churches sent a letter in 2004 signed by leaders of 20 of the largest churches in Canada urging Martin to decline a U.S. invitation to participate in NMD. Archbishop Brendan O'Brien, Canadian Conference of Catholic Bishops president at the time, signed the letter on behalf of the Canadian bishops.

Following North Korea's nuclear test explosion the Canwest chain of newspapers ran editorials urging the Conservative government to reopen negotiations with the United States on the anti-missile system. Former Canadian ambassador to the United States Frank McKenna has also urged the Liberals to consider adopting a pro-missile defence stance. The Senate defence committee under the leadership of pro-missile defence Liberal Colin Kenny released a report recommending Canada reopen missile defence negotiations.

If Catholics are part of the debate, they should be on the side of international law and negotiation rather than unproven and expensive technology, said Barringer.

"We are trying too hard in North America to guarantee our security at the price of our morals," Barringer said.

Polaris Institute defence analyst Steve Staples told The Catholic Register the North Korean nuclear test changes nothing in the ballistic missile defence debate.

"As long as there have been Americans who want to build missile shields there have been Canadians who wanted to help them," Staples said. "The same tired arguments are being trotted out by the proponents of missile defence."

Staples argues that there's more evidence than ever that the U.S. system is the first step toward putting weapons in space, and that the system is an expensive gift to defence contractors that will never work.

"The missile defence system is as unreliable as it's ever been. Donald Rumsfeld was supposed to declare it operational in 2004. They still haven't. It's almost 2007," said Staples.

The peace lobby could use a stronger Catholic voice on the issue, perhaps a full-fledged Canadian arm of the international Pax Christi movement, said the veteran peace campaigner and author of the new book Missile Defence: Round One.

"I would be thrilled if there were a Pax Christi in Canada, because I'm familiar with their work on the international stage, particularly their anti-nuclear work, and they've made a tremendous contribution," he said.

Catholics for Peace, Toronto hopes to spawn other chapters across Canada and eventually gain full accreditation from Pax Christi's international headquarters in Brussels. Pax Christi is the Vatican-recognized Catholic peace movement with more than 60,000 members in 50 countries.

"These issues are mainstream," said Staples. "They're not fringe, radical issues. They should be taken up by people who wear neckties to Mass on Sunday, as they are fundamental, Canadian issues."

"Using the nuclear test to argue for Canadian participation in missile defence is little more than opportunistic advocacy," said Michael Byers, Canada Research Chair in global politics and international law at the University of British Columbia.

Byers believes Catholics can be influential on the issues of missile defence and nuclear proliferation.

"(The Vatican's) support for the NPT (nuclear non-proliferation treaty) and international law is widely respected," Byers wrote to The Catholic Register in an e-mail. "It speaks from a transparently moral basis, rather than out of any obvious national interest."

The issue behind the missile defence question is about the fundamental goals of Canadian defence and foreign policy, said Byers.

"Should we be supporting the kind of U.S. foreign policy that has helped to motivate the nuclear weapons programs of countries such as North Korea and Iran?" Byers asked. "The push for peace-oriented, multilateral, rule-of-law foreign policies in Canada and the United States requires allies from across our societies, including from church groups."