This is by far the least important of its lessons.

It is great in many ways.

It is greatest as a remonstrance and an answer against the thriving sophisms of barbarous national pride, the eternal fallacies of war and conquest; and here it is great, as all the three pieces on the subject are so, because they expose with unanswerable force the deep-lying faults of heart and temper, as well as of understanding, which move nations to haughty and violent courses.
The great argument with those of the war party who pretended to a political defence of their position, was the doctrine that the English Government was sovereign in the colonies as at home; and in the notion of sovereignty they found inherent the notion of an indefeasible right to impose and exact taxes.

Having satisfied themselves of the existence of this sovereignty, and of the right which they took to be its natural property, they saw no step between the existence of an abstract right and the propriety of enforcing it.

We have seen an instance of a similar mode of political thinking in our own lifetime.
During the great civil war between the northern and southern states of the American Union, people in England convinced themselves--some after careful examination of documents, others by cursory glances at second-hand authorities--that the south had a right to secede.