Canada's NAFTA leak is regrettable: U.S. envoy

OTTAWA (Reuters) - The leak of a Canadian memo casting doubt on the sincerity of Democratic presidential contender Barack Obama was regrettable but Washington does not think it was done deliberately by Ottawa, the U.S. ambassador to Canada said on Thursday.

David Wilkins earlier told the Canadian Broadcasting Corp. that the leak "was interference" but told Reuters the statement had been unintentional. He stressed he had not meant to imply Canada was trying to affect the presidential election.

"It (the leak) was a regrettable matter, it shouldn't have happened, apologies have been made, regrets have been expressed," he said in an interview.

Prime Minister Stephen Harper has ordered an investigation into how reporters obtained a memo detailing a discussion between Canadian diplomats and a member of Obama's team. The memo said the Obama adviser indicated that the candidate's criticism of NAFTA was primarily political.

Obama's team denied he was being insincere, but rival Hillary Clinton said the memo showed her opponent could not be trusted. Both candidates blame the free trade agreement for U.S. job losses and vow to change or even abandon the deal, an act that could hurt Canada's economy and damage ties between the world's two largest trading partners.

"Our relationship is much stronger than one issue, it is much stronger than one incident ... These things happen, it's a bump in the road," said Wilkins. "We need to -- as quickly as we can -- all get it behind us and continue to work together."

The affair is an embarrassment for Harper's right-leaning Conservative government, which won the 2006 election on a platform that included bringing a higher ethical standard to politics and improving relations with the United States.

Critics, who accuse Harper of being too close to Republican U.S. President George W. Bush, said the spat would damage U.S. ties if Democrat Obama won the presidential election. Harper said the leak was very unfair to Obama's campaign.

Canadian media reports said on Thursday that the furor was triggered by private remarks that Ian Brodie, Harper's chief of staff, made to the CTV Television network last week about Clinton's criticism of NAFTA.

They said Brodie revealed someone from the Clinton campaign was "telling the embassy to take it with a grain of salt". CTV investigated the remarks and then ran a story focusing on Obama, saying his adviser had privately told Canadian diplomats that a promise to reopen NAFTA was solely aimed at winning votes in the Ohio primary.

In Parliament on Thursday, outraged opposition legislators pressed Harper to dismiss Brodie.

"Does the prime minister accept that he must fire his chief of staff, not only for having bothered his boss but also for having shamed his country?" demanded deputy Liberal leader Michael Ignatieff.

Harper dismissed the idea that anyone in government would want to deliberately influence an U.S. election campaign.

"It's completely against the interests of the government of Canada. It's a very serious matter," he said.

A Clinton adviser said the furor had helped her win Tuesday's primary contests in Texas and Ohio. CBC quoted an unnamed Obama adviser as saying the leak was "really, really stupid".

The chances of Brodie losing his job would appear to be remote. Harper, who does little to hide his contempt for the media, is fiercely loyal to his staff.

(Additional reporting by Randall Palmer; editing by Rob Wilson)