Why does the USDA need to tell us what constitutes a sandwhich? This is another example of the government trying to tell us what we can and can't do. They want to tell us what we can eat and what we can't eat. This is downright ridiculous. I don't need the USDA telling me what a sandwhich is.
If the USDA were to classify what constitutes a sandwich, chefs, restauranteurs and other food producers would have difficulty in marketing create new and innovative foods that are similar to sandwiches,but that do not fall into a USDA created classification. This will limit creativity and will not therefore be beneficial to society.
If the tomato paste on pizza can be considered a vegetable (way to go, Congress), I would argue that any number of ingredients "sandwiched" between two common substances (e.g., bread, bun, biscuit) is some sort of sandwich. If someone wants to get specific and call something a Reuben, BLT, or cheeseburger, go for it. Get out of my food, USDA.
No, the USDA should not be able to classify what constitutes a sandwich. The USDA is responsible for regulating the safety of our food supply and the accuracy of information about the food's content. Categorizing food should not be one of their responsibilities. Leave it to the BBB to determine fair business practices or something.