My understanding is that early unions (prior to the New Deal and labor law reform) didn't have much legal protection, and instead resorted to massive strikes. C

My understanding is that early unions (prior to the New Deal and labor law reform) didn't have much legal protection, and instead resorted to massive strikes. Companies fought back with firings and sometimes violence. Over time labor laws were built up because having major portions of your economy at war does not lead to a stable and productive society. As we disassemble those laws, we'll probably learn why they were created.