1.25" with interesting back story behind button reading "California Conference On Social Work/San Jose/May 9-13, 1937." At this event Eric Thomsen, California Regional Sociologist of the United States Resettlement Administration presented a paper titled "Why Pay Security For The Migratory Laborer." His paper pointed out the plight of farm laborers with no accident, health or unemployment insurance and with only a future in the poorhouse to look forward to. He argued that the solution was up to Federal and State legislation to guarantee these basic rights and that the Social Security Act and Wagner Labor Relation Law should be amended to include migratory labor. Earliest button we know of to relate to this issue and very limited in its distribution. Essentially Mint. See next related item.