In addition to the writing of the Declaration of Independence, 1776 also saw the publication of Adam Smith's Wealth of Nations. Writing just a few months before the Declaration, the founder of modern economics and a key influence on modern libertarianism and conservatism endorsed American independence for somewhat different reasons than Jefferson & Co. did:
It is not contrary to justice that both Ireland and America should contribute towards the discharge of the public debt of Great Britain. That debt has been contracted in support of the government established by the Revolution [of 1688], . . . a government to which several of the colonies of America owe their present charters, and consequently their present constitution and to which all the colonies of America owe the liberty, security, and property which they have ever since enjoyed. That public debt has been contracted in the defence, not of Great Britain alone, but of all the different provinces of the empire; the immense debt contracted in the late [French and Indian] war in particular, and a great part of that contracted in the war before, were both properly contracted in defence of America . . .
If the colonies, notwithstanding their refusal to submit to British taxes, are still to be considered as provinces of the British empire, their defence in some future war may cost Great Britain as great an expence as it ever has done in any former war . . .
If any of the provinces of the British empire cannot be made to contribute towards the support of the whole empire, it is surely time that Great Britain should free herself from the expence of defending those provinces in time of war, and of supporting any part of their civil or military establishments in time of peace . . .
Adam Smith, The Wealth of Nations, Book V, Chapt. III (1776).