Texas hold’em has a specific reason for a dealer button. Like just about any Houston poker room (or for that matter at all, any casino poker room anywhere) there is a designated dealer provided who actually does the dealing. Since there are forced blinds, the dealer button creates a “pretend” dealer so that who is forced to make those forced blinds rotates every hand and everyone participates. That’s not what created the dealer button, though.
In the Old West (and isn’t it amazing how much in the world of poker originated in the Old West?) cheating was believed to be rampant. Since the easiest time to cheat would be by colluding with a dealer, dealers were most often mistrusted. A way to address that was to rotate dealers and the most common way to do that was to pass a knife around the table in a circle. Since most knives had buck antler handles, that meant passing the buck.
In the 1880s and 1890s, the knife gave way to a silver dollar coin. There are many scholars who believe that’s how buck became associated with money. It also gave way to a round flat object signifying the dealer like the button we use today. In the old west, though, when poker was mostly draw, the one with the buck was the dealer and responsible for the integrity of the hand. Once he passed the buck, he passed that responsibility away as well.
These days, passing the buck means sending the responsibility to deal with a problem or situation to someone else. President Harry Truman famously put a placard on his desk in the Oval Office that said, “The Buck Stops Here.” You have to wonder if he knew poker inspired that sign…