Final answer:
Las Casas argued against the mistreatment of Native Americans by the Spanish, and his criticism influenced international relations in the Americas.
Step-by-step explanation:
According to Bartolomé de las Casas, the implications of Sepulveda’s arguments for international relations were significant. Las Casas, in his book A Short Account of the Destruction of the Indies, criticized the brutal treatment of Native Americans by the Spanish. He argued that the Spanish were causing immense suffering and distress to the natives, and he called for an end to this mistreatment. Las Casas' work influenced other European nations to challenge Spain's colonial empire, leading to a reevaluation of international relations in the Americas.