Patri Friedman of seasteading fame, has an interesting post reopening an old debate: whether the Declaration of Independence launched a revolution or a secession movement. This was a hotly contested issue in the 19th century, when southern secessionists claimed they were following in the footsteps of the Founding Fathers who seceded from the British Empire, while many northerners responded by drawing a sharp distinction between secession and revolution.
The truth is that the Declaration of Independence was both a revolution and a secession. There is little question that American Patriots sought to secede from the British Empire in the sense that they wanted to break off their part of it and form a separate nation. Certainly, they weren’t trying to replace the existing British government with a new one, while keeping the empire intact. On the other hand, the American independence movement was also revolutionary in the sense that it sought to institute a radically new political system. The revolutionaries certainly were not trying to gain independence simply for the purpose of establishing a smaller country with a political system that largely copied Britain’s. For example, the rebels sought to create a polity with far stronger protections for individual freedom, no hereditary aristocracy, and a much more democratic political system than existed in 18th century Britain (or any other European state). Historian Gordon Wood discusses these and other radical changes sought by the revolutionaries in his excellent book The Radicalism of the American Revolution. Of course, the new United States did not consistently pursue liberal principles across the board, as witness the continuation of slavery in the South. But it did pursue them to a far greater extent than the British government of the day.
In sum, therefore, the revolution-secession dichotomy fails to capture the true nature of the American independence movement, which was an attempt to use secessionist means for revolutionary ends.