Sentence:  After 50 years, <WSD>legal</WSD> segregation is a distant memory, and race in America is not the unbridgeable chasm it once was. The country has a black president. The sort of comity that King evoked, in which the descendants of slaves and of slave owners “sit down together at the table of brotherhood”, can be found in many places, including the Deep South. The rate of marriage between blacks and whites is rising. 
Meaning of the word marked with <WSD> tags:  Being allowed or prescribed by law.