What effect did the twonhead acts have on American colonies?

The Townshend Acts applied duties (taxes) to paper, paint, lead, glass, and tea imported by the colonies. Townshend had studied the colonists distinction between internal and external taxes and he believed his duties were external none of the products, except tea, could be made in the colonies. The colonists did not agree with his thinking and the result was a colonial boycott against British products. Trade between England and America fell off by 50 percent as a result of the boycott. The British merchants complained to Parliament who repealed the Townshend Duties except the tax on tea. The tea tax was kept in honor of the Declaratory Act. Parliament passed that act to declare that they did have the right to tax the colonies regardless of the American claim of internal or external taxation.