The Conservative government is sending strong signals that it will not support a bid to create a new national security committee of parliamentarians.
A succession of Tory MPs spoke out in the House of Commons to dismiss the idea, put forward in a private member's bill by Liberal public safety critic Wayne Easter.
Easter's bill, introduced in November, would give committee members access to top-secret information – unlike existing panels of MPs and senators.
The Liberals used an allotted day in the House on Tuesday to propose that members embrace the concept. The motion came just a day after the head of Canada's eavesdropping agency denied breaking the law to spy on Canadians.
The Conservative majority ensured its defeat by a vote of 146 to 130.
Ottawa-based Communications Security Establishment Canada, known as CSEC, monitors foreign computer, satellite, radio and telephone traffic of people, states, organizations and terrorist groups for information of intelligence interest.
The Conservatives repeatedly note the watchdog that oversees CSEC has consistently found that the spy agency has operated within the law and has respected the privacy of Canadians.
During debate in the House, Liberal MP Joyce Murray belittled the watchdog's office, currently led by Quebec judge Jean-Pierre Plouffe, and accused the government of trying to block proper oversight.
"This is not a robust watchdog," she said. "This is a starving, ineffective watchdog."
The government says Plouffe and his team are effectively monitoring CSEC and that a new parliamentary committee would be a waste of resources.
Roxanne James, parliamentary secretary to the public safety minister, said the private bill would create a "partisan group of politicians" to keep an eye on a watchdog that has concluded CSEC is obeying the law.
"They're creating a second level of bureaucracy," she said.
Some MPs and senators with an interest in national security complain they cannot hold intelligence services fully to account because they lack clearance to see secret information.
New Democrats backed the Liberal call for stronger parliamentary oversight, which dates from a proposal hatched during the short-lived Paul Martin government.
NDP MP Murray Rankin wondered whether the government was opposed to giving MPs top-secret security clearances because they simply do not trust members.
During question period, NDP Leader Thomas Mulcair pressed Prime Minister Stephen Harper on CSEC's surveillance of metadata – data trails about calls and messages – during a 2012 exercise, saying such information can be highly revealing.
"That means that it knew where and when Canadians were using the Internet and who they contacted," Mulcair said.
"Who in the government authorized that operation by CSEC?"
Harper did not answer directly, but said Plouffe "continues to examine all of CSEC's activities and has said that they are clearly within Canadian law, as we would expect them to be."
At a Senate committee meeting Monday, CSEC chief John Forster said the exercise in question – aimed at learning more about public communication patterns – would have been guided by a broad ministerial directive authorizing the agency to collect metadata.