This excerpt is talking about how instead of the king just throwing around crazy tax prices, a group of people ( the great council) who represent the best interests of the general population will come together and come up with reasonable tax prices based on a vote. The king will have no choice but to accept.
Langston and Martin were very close and even traveled to Nigeria together in 1960. Martin loved Langston's work because it really spoke to him and related to the civil rights movement.