The term comes from the Texas cattle business. Now, instead of using a red hot iron to show who we belong to, we wear a large identifying label across our chests on expensive t-shirts and sweaters. The shorts with the brand on the seat put the name right about where the cattle wore it. Americans show their independence by identifying themselves as members of herds. Sometimes we belong to several herds at once. I don't think Texas cattle were ever as cooperative or loyal or easily led as we are.