Did Barack Obama’s campaign quietly contact Canadian officials to tell them not to take seriously the Illinois senator’s tough talk about renegotiating trade agreements?

CTV, the well-regarded Canadian news network, reported this week that a top Obama adviser contacted the Canadian government to calm fears that the senator was serious about rewriting pro-corporate deals such as the North American Free Trade Agreement to benefit workers, farmers and the environment. According to CTV, the Obama adviser told the Canadians that “when Senator Obama talks about opting out of the free trade deal, the Canadian government shouldn’t worry. The operative said it was just campaign rhetoric not to be taken seriously.”

After that report aired on Wednesday, an Obama campaign spokesperson claimed in an interview with CTV that “no message was passed to the Canadian government that suggests that Obama does not mean what he says about opting out of NAFTA if it is not renegotiated.”

The problem, of course, is that CTV has a very credible source — a a high-ranking member of the Canadian embassy — who has provided the network with details of the call and a timeline.

Of course, the source is now being pressured to tell a different story by superiors. But few serious observers of the trade debate — with its history of back channel communications — doubts the scenario as it was first reported.

Attempts by CTV to get the Obama camp to respond to specific questions about the conversation and the timeline in question have so far proven unsuccessful.

According to CTV, “the Obama camp did not respond to repeated questions from CTV on reports that a conversation on this matter was held between Obama’s senior economic adviser — Austan Goolsbee — and the Canadian Consulate General in Chicago.”

CTV did contact Goolsbee, but he’s not cooperating.

The network reports that “(Goolsbee refused to say whether he had such a conversation with the Canadian government office in Chicago. He also said he has been told to direct any questions to the campaign headquarters.”

It is starting to sound an awfully lot like the Obama campaign may have gotten caught telling Canada one thing and Ohio something different.

What’s the bottom line on this story? According to the network: “Sources at the highest levels of the Canadian government — who first told CTV that a call was made from the Obama camp — have reconfirmed their position.”

And what’s John McCain saying?

“I don’t think it’s appropriate to go to Ohio and tell people one thing while your aide is calling the Canadian ambassador and telling him something else,” says the likely Republican nominee. “I certainly don’t think that’s straight talk.”

On this point, McCain’s right.