All Had To Come To An Agreement And End The WWI
Castiglione thought that the ruling class should follow a standard of conduct.
Machiavelli believed that the rulers must look like they are generous but that they must do what they need to do to keep order.
The answer is the North Vietnamese took over the South Vietnam spreading communism Southward and this proved the domino theory (if one country come under the influence of communism, the surrounding countries would follow).