GEORGE FLOYD was not famous. He was killed not in the capital of the United States, but on a street corner in its 46th-largest city. Yet in death he has suddenly become the keystone of a movement that has seized all of America. Still more remarkably, he has inspired protests abroad, from Brazil to Indonesia, and France to Australia. His legacy is the rich promise of social reform. It is too precious to waste.
What does "legacy" and "rich promise" mean?