The origins of the secret ballot
Launch library · evergreen read

For much of early electoral history, voting was often done openly, by a show of hands or a public declaration, which left voters exposed to pressure from employers, landlords, or local strongmen. Reformers argued that a truly free choice required a way to vote without anyone else watching over their shoulder or noting their exact decision.
The secret ballot, sometimes called the Australian ballot in recognition of colonial Australia's early adoption of the practice, introduced a uniform government printed paper marked in private and folded before being placed in a sealed box. The simple mechanics of privacy proved remarkably powerful once they were widely adopted across many different jurisdictions.
Once secrecy became standard, the character of campaigning itself began to shift, because intimidating a voter no longer guaranteed a particular outcome for anyone involved. The reform is now so embedded in expectations of a fair election that it is easy to forget how contested it once was, and how recently it became the accepted norm we take for granted.