When I was in high school, I used to attend Junior State of America conventions (basically debate/model congress + speakers and political activists). I remember sitting in the audience during a particular debate about free trade, listing to a debater explain that international trade causes Americans to lose their jobs, and that "buying American" is every citizen's duty.
During the Q&A part, I asked the speaker where her shoes were made. She took them off, read the label, sheepishly said "Mexico" (yes!), and quickly told the audience, "But I wish they were made in America!"
I was reminded of the story by this video (admittedly infantile, but true) linked at Cafe Hayek. No one made the speaker buy foreign-made shoes. There are American shoes out there, but foreign ones are a lot cheaper. The entire shoe-wearing world is made better by free trade.
This is the problem with entire industries demanding protective tariffs. I guarantee that if you approached a random unionized auto-worker at some protest decrying the evils of free trade, his clothes would be foreign-made. If you followed him home, his appliances would probably be foreign made. Even if his car were made by GM, the parts used to make it come from many different countries. People will shout stupid things at protests, but when it comes to living their lives, they have no choice but to acknowledge the vast benefits free trade has brought everyone.
I believe good ol' Milt said it best in this video. (except for the sentence about commissars)