Traditionally, in the US, “e pluribus unum” has been understood to mean that out of many states (or colonies) emerged a single nation, a metaphorical melting pot. In recent years, its meaning has come to suggest that out of many peoples, races, religions, languages, and ancestries a single people and nation is emerging, a metamorphosing  salad bowl.

“De Officis” (Concerning Duties - 44 BCE), discusses basic family and social bonds as the origin of societies and states. Cicero paraphrases Pythagoras (c. 570 – c. 495 BC): "When each person loves the other as much as himself, it makes one out of many, 'unus fiat ex pluribus', as Pythagoras wishes things to be in friendship.”

“De Officis” was the second book Gutenberg printed. Sts. Ambrose, Augustine, Jerome and Thomas Aquinas referred to this concept in their writings. At the Last Supper, Jesus prayed, “Ut unum sint,” — that they all may be one. (Jn. 17:20-26)

BTW, the correct way to say “America First” in Latin is “America primum.”