11:27 ET -- The Canadian dollar is weaker in trading amid an escalation in trade tensions between the U.S. and Canada. However, risks abound in attempts to short CAD, says Brent Donnelly, head of forex-research firm Spectra Markets. "I would not be chasing short CAD here," he says. "The CAD trade features too many crosswinds to make any sense, whether it's vs. GBP, JPY, USD or anything else." He adds CAD hasn't taken a substantial drubbing because forex traders are accustomed to President Trump's on-and-off trade threats. "It's hard for the market to get excited and/or scared of a theme when the theme is 18 months old and the tariff threats go on and off like Delta Wi-Fi."