The country America broke away from actually still has a
current active law stating the
heir to their
throne can not marry a Catholic, or be anything other than a member of their state sponsored Church.
During an unsettled time of apartheid, Seretse's Uncle, the
current King, rejects his nephew's marriage and creates a pact with the United Kingdom
to keep the
heir from the
throne, despite the wishes of the Botswana people.