According to this CBC story, a prosecutor in Texas is accused of using the word "Canadian" as a racial slur in a 2003 email. The prosecutor wrote in an email, "He overcame a subversively good defense by Matt Hennessey that had some Canadians on the jury feeling sorry for the defendant and forced them to do the right thing."
There were no Canadians on the jury. But there were some African-Americans, and some are claiming the lawyer used the word "Canadian" as a racial slur against them.
The prosecutor defended himself by saying he had been led to believe that were actual Canadians on the jury, suggesting that somehow some Canadian nationals had slipped through the system designed to eliminate non-U.S. citizens as prospective jurors. He also said that other lawyers use the word "Canadians" to describe "liberals."