No it's not. The argument has always been a safety issue.
The US anti-Mexican truck contingent (the trucking unions and it's drivers), contend that the Mexican trucks are unsafe, when in fact they are worried about lost wages.
My point was that, if the DOT inspects the Canadian trucks, why can't they inspect the Mexican trucks? And if they do inspect them, hold them to the same standards as we hold the Canadians.
Guatemalan trucks don't enter into the equation.