How did the Townshend Act lead up to the Revolutionary War?

The Townshend Acts of 1767 grew out instability in London's government. William Pitt was named prime minister in 1766, but he no longer had his full cognitive abilities. Because of Pitt's inability to govern, Charles Townshend (1725–67), chancellor of the exchequer, emerged as the leading voice of the cabinet. Townshend was erratic and had a great deal of contempt for Americans. He sought to reassert London's control over the colonies and collect revenue, too.
There were four separate Townshend Acts. The first one shut down the New York assembly for its non-compliance with the Quartering Act (1765). The second one was the Revenue Act. This was a tax levied at American ports to raise revenue for London. The third act set up an enforcement mechanism to collect tariffs and monitor colonial trade. The fourth act was designed to help the East India Company's trade in tea.
The colonists protested vehemently, and the agitation led to the Boston Massacre in 1770. The Townshend Acts were repealed in 1770, except for the tax on tea, which persisted. In 1773, the Boston Tea Party made it clear that relations were still tense.
Relations between London and America were irreparably damaged by the Townshend Acts and the violent incidents that resulted from them. War broke out in 1775.