Ottawa can't seem to persuade Americans that it's a myth that terrorists lurk in Canada posing a grave threat because of a porous border.
In the latest brouhaha, Ambassador Gary Doer upbraided Sharron Angle, the Republican with a solid chance of unseating Nevada Senator Harry Reid, after the outspoken Tea-Party-backed candidate suggested that Islamic jihadists have entered the United States from Canada.
"We do not have a 'porous border,' but rather one of the more secure borders in the world," Mr. Doer insisted in a letter he fired off to Ms. Angle, as well as posting it on the embassy's website. "Canada takes border security very seriously and [I]trust you will see fit to set the record straight," he added.
So far she has not done so, and she may see no need.
Ms. Angle didn't say the Sept. 11, 2001, suicide hijackers came from Canada, although that remains a persistent belief among Americans. What Ms. Angle said was that the northern border is America's "most porous" and that terrorists have come from Canada.
That's more or less what Homeland Security Secretary Janet Napolitano said as recently as a year ago. When outraged Canadian officials took her to task, the unrepentant Ms. Napolitano held her ground. "I know that the Sept. 11 hijackers did not come through Canada to the United States" she said, adding pointedly: "There are other instances, however, when suspected terrorists have attempted to enter our country from Canada.''
Ahmed Ressam, the Millennium Bomber, is perhaps the best known. Carrying a genuine Canadian passport, he packed a rental car full of bomb-making equipment and took a ferry from Victoria to Port Angeles, Wash., where he was intercepted by an alert U.S. Customs agent.
Unimpressed by Mr. Doer's reprimand, Ms. Angle's spokesman Jarrod Agen pointed to the Ressam plot.
Although Canada and the United States have spent billions turning the 6,000-kilometre frontier, once billed as the world's longest undefended border, into a maze of concrete, cameras and radiation detectors, it may still be too porous for many Americans.
"The fact of the matter is that Canada allows people into its country that we do not allow into ours," Ms. Napolitano has said.
In fact, porosity may be a problem in both directions.
Najibullah Zazi, who plotted to bomb New York's subway system, crossed into Canada to visit relatives in Mississauga. He went back and forth across the border apparently without triggering alerts on either side. Two members of the so-called Toronto 18, who plotted to build huge vehicle bombs, bought handguns in the United States before heading home to Toronto.
An alleged pair of terrorists from Atlanta, Syed Haris Ahmed and Ehsanul Islam Sadequee, took the bus to Canada in 2005 to consult with jihadists in the Toronto 18.
Ms. Napolitano has suggested that the scale of the threat and the number of extremists who slip in and out of the United States is considerably greater than the instances that are known because of arrests. "Some of these are well-known to the public - such as the Millennium Bomber - while others are not due to security reasons."
That's more or less what the Tea Party's would-be senator from Nevada is saying too.