President Lyndon Johnson, Democrat, signs the Social Security Act of 1965, establishing Medicare and Medicaid - 1965
"Two decades earlier, President Harry S. Truman began the debate that led to the passage of Medicare when he called for a national health insurance plan." - from http://www.nolo.com/legal-encyclopedia/content/ssa-1965-act.html
"The Conference Committee to reconcile the differing bills of the two houses completed its work on July 26th. The reconciled version of H.R. 6675 then went to final passage in the House on July 27th and final passage in the Senate the following day. (The detailed vote tallies on final passage are reproduced below.)" - from http://www.ssa.gov/history/tally65.html