The American Revolution occurred because of Great Britain's failure to adjust to conditions brought on by the growth and development of the colonies, and by the aggravation of a breakdown in the political and economic harmony that existed between the colonies and their mother country.
America was a revolution force from the day of its discovery. The American Revolution was not the same thing as the American War of Independence. The war itself lasted only eight years, but the Revolution lasted over a century and a half and begun when the first permanent English settlers set foot on the new continent. Insurrection of thought usually precedes insurrection of deed. Over the years such ferment had occurred in the thinking of the colonists that the Revolution was partially completed in their minds before the first shot was fire or musketball began to fly.
The American Revolution had its beginnings in the French and Indian war. For seven years, Britain battled the French and Indian nations in the colonies. Where the colonies militia fought beside the troops of the British army and learned war first hand. After winning the war, Britain had a huge debt to pay. To pay these expenses, George Grenville, who was secretary of Treasury in England, came up with a plan. He reasoned that the debt should be paid by taxing the colonies. After all the war had been fought to protect their land, that is the land of the Ohio River Valley.
However, even before the French and Indian War had ended the political harmony that was once between the colonies and the British was already being broken down, due to all of the new acts that were passed in accordance with the mercantile theory of economics. This theory of economics said that colonies are only here to serve and glorify their mother country, in this case Britain. This lead to Britain's passing of the Navigation Laws. These laws mandated