What significant act did Andrew Young accomplish in U.S. politics?

Andrew Young is widely recognized for his role as U.S. Ambassador to the United Nations, a significant position that allowed him to play a critical role in international diplomacy and U.S. foreign policy. Appointed by President Jimmy Carter in 1977, Young was the first African American to hold this office, which marked a historic breakthrough in U.S. politics, particularly regarding representation at high levels of government. His tenure at the UN was characterized by his advocacy for peace and human rights, as well as his efforts to address issues such as apartheid in South Africa.

This position is notable not just for Young's personal achievement, but also for its broader implications during a time of racial and social change in the United States. It helped pave the way for future African American leaders in foreign policy, reflecting the progress being made in civil rights and representation throughout the country.

The other options, while significant in other contexts, do not reflect Young's most prominent achievement in U.S. politics. He was indeed the first Black mayor of Atlanta and played a crucial role in Georgia's political landscape, but his impact at the United Nations as an ambassador is particularly distinguished in the context of U.S. history.