Without Free Trade we would be less prosperous. Prosperity is what convinces people the value of economic policies. When the first Free Trade agreement with the U.S.A. was the "dominant" election issue in 1988, Liberals and New Democrats declared that it would "ruin" the country and make us simply a puppet for the U.S.A.. Lots of them even had tears in their eyes as they predicted American troops would be coming across the border because of Free Trade. They thought Canada would be too economically tempting for the U.S.A.. to resist. Well, Liberals love free trade nowadays and if the NDP had won  the last election, they wouldn't have touched things.
Oh and I'm a middle-class fellow myself.