Just before the March 4 Primary, Clinton was hammering Obama by seizing on an CTV (Canadian TV network) story that made Obama look like a bit of a phony. They called it NAFTA-Gate. The story claimed that an Obama staffer had called the Canadian embassy, telling them to ignore all campaign talk about NAFTA. Clinton made quick use of the story and Obama's denials that the call ever took place. On the eve of the Ohio primary, the perception that Obama was being a phony on an economic issue quite possibly resonated with voters who decided in the last few days (as a large number of Clinton voters said they did.)
Fact Check.org researched the story and found there was no evidence of such a phone call, and denials on both the Obama side and the Canadian side. Obama was flummoxed when confronted with the accusations, which I'm sure looked great to Ohio voters.
FactCheck did find that there was a memo circulating within the Canadian government, nearly a month earlier (Feb 8). The memo contained notes taken on a meeting between Canadians and Obama's financial advisor, Austan Goolsbee. Goolsbee has called the memo's notes on his comments: "a pretty ham-handed description of what I answered" and "completely crazy." The comments were, in essence, reassuring Canadian officials that Obama's stance was the same as they had previously discussed in private. Whoever took the notes included the phrase "political posturing."
So, why was there talk of a phone call taking place in late February after NAFTA had come up in the debate? MSNBC is reporting:
"[PM Harper's chief of staff] Mr. Brodie, apparently seeking to play down the potential impact on Canada, told the reporters the threat was not serious, and that someone from Ms. Clinton's campaign had even contacted Canadian diplomats to tell them not to worry because the NAFTA threats were mostly political posturing. The Canadian Press cited an unnamed source last night as saying that several people overheard the remark.