James I reigned as king of England from 1603 to 1625. He was the son of Mary Queen of Scots, and he had been king of Scotland before succeeding to the English throne at the death of Queen Elizabeth I. He was prompted to produce an English Bible because of the poor and tendentious copies being circulated in England. He feared these could be used by seditious religious and political factions.
His authority was one usurped from the Catholic Church, beginning with his predecessor King Henry VIII. Henry had broken with the Catholic Church and made himself the head of the Church in England, which soon enough became the Church of England. You could say James had no more authority in biblical matters than any head of state, basically none. What authority would a "George Bush Bible" have? The true authority and safeguard over Scripture was and has to be the Catholic Church, to which Christ gave his authority. No secular authority has any rightful authority over the Bible.