On June 19th, 1865, federal troops arrived in Galveston, Texas to ensure that all enslaved people were freed, ushering in the end of slavery. Now, Congress has made it a holiday. On Today's Show: Elizabeth Alexander, president of The Andrew W. Mellon Foundation, poet, educator, memoirist and scholar, looks back through American history — both recent and not — and asks the fundamental question "what does it mean to be Black and free in a country that undermines Black freedom?"