The taxation began in the 1760s, the Boston Massacre occurred in 1770, the Boston Tea Party in 1773, and the Battles of Lexington and Concord in April of 1775.
Patrick Henry's call to action, "Give me liberty, or give me death," was the first strong public statement that, if we were to be free, if we were to have liberty, then we would have to fight Britain. Prior to Henry's speech to the gathering of Virginia delegates in Richmond, the prevailing belief was that we could negotiate with Britain.
Henry lay down the gauntlet and clearly presented his understanding of what we were facing.
Our choice was liberty or death.
Our Declaration of Independence is a three-part document: the first a declaration of freedom, including our understanding of the natural order of authority and power; the second a long list of grievances, reinforcing the belief that there was no choice but to declare our independence as a free country; the third an acknowledgment of risk and the oath of the signers to one another.
The first section is the one that is most often quoted: "We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness. -- That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed, -- That whenever any Form of Government becomes destructive of these ends, it is the Right of the People to alter or to abolish it, and to institute new Government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Safety and Happiness."
This introduction represents the core of American Exceptionalism. We are exceptional as a nation not because we are inherently better people (people are the same everywhere), but because our government is built on a different structure than those of other countries. Our founders understood and articulated our belief in a creator (God), who endows people with rights. The people then loan the rights to the government to secure their individual rights (life, liberty, pursuit of happiness).
The introduction also provides for recourse if government becomes destructive to individual rights, "to alter or to abolish it," meaning the government.
The second part, less often referenced, lays out the reasoning for why we were seeking independence, a reasoning that included a long list of King George III's grievances.
"Prudence, indeed, will dictate that Governments long established should not be changed for light and transient causes; and accordingly all experience hath shewn, that mankind are more disposed to suffer, while evils are sufferable, than to right themselves by abolishing the forms to which they are accustomed. But when a long train of abuses and usurpations, pursuing invariably the same Object evinces a design to reduce them under absolute Despotism, it is their right, it is their duty, to throw off such Government, and to provide new Guards for their future security. ... The history of the present King of Great Britain is a history of repeated injuries and usurpations, all having in direct object the establishment of an absolute Tyranny over these States."
A detailed list of grievances for all the world to view followed.
Our founders concluded the document with the pledge to each other, and an invocation of God. "And for the support of this Declaration, with a firm reliance on the protection of divine Providence, we mutually pledge to each other our Lives, our Fortunes and our sacred Honor."
Knowing that their declaration would be seen as an act of treason by the king, the signers also knew that, if they were not successful, they would risk losing their lives.
This document declared us free, outlined the foundational understanding of our rights, from whom they came, and our responsibilities to maintain them.
These days, of ongoing budget deficits, increasing regulation and taxation, retaining our independence might be more challenging than the original declaration.