Answer:
In justifying American independence, he drew inspiration from the political philosophy of John Locke, an advocate of natural rights, as well as the enlightened ideas of other British thinkers. The declaration included a long list of grievances addressed to British King George III that provided the reasons for rebellion.
Or.....
American opposition to British policy began in 1765, when the Parliament in London passed the Stamp Act to raise revenues for a standing army in the colonies. In October, rallying under the banner of “no taxation without representation,” colonists convened the Stamp Act Congress to express their opposition to the tax.