After 1763, the British government began trying to repay the enormous war debt they incurred after The French and Indian War. Parliament felt that the American colonies had a responsibility to help repay this debt, and they began passing measures to tax the colonies to pay for national defense. The Stamp Act, Tea Act and Townshend Acts are examples of these taxes.
Up to this point, the colonies had never been taxed directly by parliament, so there was a considerable amount of resistance to these measures. The colonies began to unify in their opposition through boycotts, protests and rioting. The British quickly repealed most of these measures, since the boycotts were costlier than the tax revenue collected.
However, the British were upset with the pattern they were seeing. The defiance of the colonies might incite other colonies to resist British control. The Declaratory Act as well as a series of laws called the Coercive Acts went into effect after the famous Boston Tea Party. These laws smacked of tyranny, and led to the arming of colonial militias, which eventually led to the battles of Lexington and Concord and eventual independence.