“Plumbers need to be licensed in nearly every state”
Not in California.
You are incorrect.
Just so we are clear, no, someone working as aplumber for a plumbing business does not need to carry alicense, but all plumbing business need to be licensed. Some license categories cover plumbing as a general contractor license, or, if it’s just plumbing, they need the proper plumbing license for the type of work being done.
I sure as heck don’t ask my plumber for his licence when he walks in the door. He had been here three times and does good work! I bet he is smart enough to vote for McCain too.