Lyndon B. Johnson played a crucial role in the establishment of Medicare and Medicaid in the U.S., signing the programs into law in 1965 as part of his broader Great Society initiatives. These programs aimed to provide health insurance to the elderly and low-income individuals, respectively, addressing significant gaps in American health care. Johnson's support was rooted in a commitment to reducing poverty and enhancing access to medical care, ultimately transforming the landscape of health services in the country and providing security to millions of Americans.