Progressive Party presidential candidate (and former president) Theodore Roosevelt endorsed health insurance in 1912. Library of Congress.
In addition to thinking about your research question think about the types of sources might contain relevant information. This page will help you find more information on how to search many of the databases on this guide.
This list points you to some of Gumberg Library's guides designed to help you with literature searching basics and specific techniques for selected databases. If you have questions, don't hesitate to Ask Gumberg.