By early 1937, he’d heard about the Spanish Civil War and decided to make his way to Spain, where he joined the Abraham Lincoln Brigade – an American volunteer military unit that fought against Gen. Francisco Franco and his fascist troops.

Source: https://www.aerotechnews.com/blog/2023/04/17/medal-of-honor-monday-u-s-army-sgt-1st-class-edward-carter-jr/

Their history received increased attention and has been discussed more openly in Spain since the death of Francisco Franco in 1975.

Source: https://forward.com/fast-forward/568622/spains-balearic-islands-officially-recognize-centuries-injustice-against-crypto-jews-majorca/