Nothing does reason more right, than the coolness of those that offer it: For Truth often suffers more by the heat of its defenders, than from the arguments of its opposers.

As a pacifist Quaker Penn considered the problems of war and peace deeply and included a plan for a United States of Europe ("European Dyet Parliament or Estates") in his voluminous writings. The democratic principles that he set forth in the Pennsylvania Frame of Government served as an inspiration for the United States Constitution. In 1704 they achieved their goal when the three southernmost counties of Pennsylvania were permitted to split off and become the new semi-autonomous colony of Lower Delaware.