The impossibility of subduing people

{This is from a letter to William Duane dated July 25, 1811:]

The papers of every day read them the counter lesson of the impossibility of subduing a people acting with an undivided will. Spain, under all her disadvantages, physical and mental, is an encouraging example of this. She proves too, another truth not less valuable, that a people having no king to sell them for a mess of pottage for himself, no shackles to restrain their powers of self-defence, find resources within themselves equal to every trial. This we did during the revolutionary war, and this we can do again, let who will attack us, if we act heartily with one another. This is my creed.