Sentiment for independence gradually grew in 1776. At the opening of the war, only a few Americans, such as the Adams cousins, believed that the colonies must separate themselves from Britain. Most clung to the belief that the American resolution demonstrated at Boston and elsewhere would persuade the authorities in London to change course. The Americans were aware that they had friends in Parliament, like the eloquent Burke, and potential allies among British merchants, who would not like the lucrative American trade disrupted. The Olive Branch Petition sent by Congress to the King embodied these hopes. Most Americans would have been happy with a political solution that guaranteed American rights and selfgovernment within the framework of the British empire.

The British government's rejection of compromise shook American attachment to the empire. The motions of men like Burke were defeated by large margins in Parliament. Petitions urging peace circulated by associations of merchants were disregarded. Word came that the King had definitely turned away from his subjects in the colonies. In a message to Parliament, George III denounced the “authors and promoters of this desperate conspiracy…. They meant only to amuse, by vague expressions of attachment to the parent state, and the strongest protestations of loyalty to me, whilst they were preparing for a general revolt…. The rebellious war now levied … is manifestly for the purpose of establishing an independent empire.” The gulf in sentiment between the Americans and their mother country had never been more manifest. Some began to question loyalty to a King who seemed to scorn their affections.

The Prohibitory Act inflicted more concrete harm. By cutting off its trade, the British government threatened America with economic ruin. John Adams pointed out that the Prohibitory Act “makes us independent in spite of our supplications and entreaties.” The British government dealt another devastating psychological blow to fraying loyalties when it began hiring German mercenaries for the war. To a people instructed by seventeenth-century English history that standing armies were instruments of oppression, the King and Parliament confirmed their tyrannical intent by unleashing foreign mercenaries on them. Britain's leaders seemed to be doing everything possible to associate themselves with the most nightmarish American fears. For a growing number of people in the colonies, the customary ties to Britain were increasingly meaningless. The British themselves were making it clear that American liberties would never be safe within the empire.

In January 1776, Thomas Paine, a journalist working in Philadelphia, published a brief argument for independence. He called it Common Sense. Plainspoken and passionate, Paine brilliantly made the case for separation from Britain. He provided his less articulate countrymen a rationale for a step that they had been inching toward. His influence was astonishing. More than 100,000 copies of Common Sense were printed in 1776 — a number as astonishing as the modern-day record first printing of 12 million copies held by J. K. Rowling's Harry Potter and the Deathly Hallows. The rapid dissemination of Paine's pamphlet throughout the colonies was a remarkable intellectual and political phenomenon.

Paine's rhetorical strategy was to cut to the heart of the dispute between the colonies and their mother country. He did not devote a lot of space to addressing the crisis over taxation. Paine believed the issues that had led to the war were merely symptomatic. He argued that the real problem was Britain's monarchical system. Paine directly attacked George III, calling the King a “Royal Brute.” He could be nothing less, since the enlightened despots of the day were the heirs of tyrants who had seized power by force, “the first of them nothing better than the principle ruffian of some restless gang.”

Paine questioned the legitimacy of monarchy, writing in words that resonated with Americans: “For all men being originally equals, no one by birth could have a right to set up his own family in perpetual preference to all others forever.” Thus the British government was by definition “rotten.” That is why the mother country could oppress its colonies with corrupt laws, and when they resisted, attack them with armies of hirelings. Paine accepted American exceptionalism. America's mission was to be the last refuge of liberty. He called America “an asylum for mankind.” Paine concluded that Americans must divorce themselves from the wickedness of Britain: “The blood of the slain, the weeping voice of nature cries, ‘TIS TIME TO PART.’”

Paine's denunciation of monarchy and call for a republic that enshrined human liberty was profoundly compelling to his contemporaries. George Washington paid tribute to the “sound doctrine and unanswerable reasoning” of Common Sense. Paine popularized the idea of independence; he helped give the movement toward separation from Britain irresistible momentum.