Why 18 Specifically?
Advocacy Target: Reformers explicitly campaigned for 18, viewing it as the age when young women could achieve greater maturity and independence. The WCTU petitioned every state legislature, collecting tens of thousands of signatures (e.g., over 50,000 in Texas alone) and sending women to testify. They argued 18 aligned with emerging ideas of adolescence as a distinct life stage, influenced by psychology and education reforms.
Moral and Protective Framing: 18 was seen as a safeguard against "self-ruin" (girls being lured into sex outside marriage) and urban vices like trafficking. Male legislators often supported it to claim credit for "protecting" women, though opposition came from those fearing it would criminalize consensual teen relationships or enable "conniving" girls to trap men.
Legislative Compromise: Ages were often arbitrary products of debate, not data. Some states settled on 18 after rejecting higher proposals (e.g., 21), balancing reformers' demands with concerns over enforcement. In Colorado (1895), the first bill by a female lawmaker raised it to 18, celebrated by suffragists like Susan B. Anthony.