The tree of liberty must be refreshed from time to time with the blood of patriots...
I've seen this quote many times, and always for one purpose: to evoke praise for U.S. soldiers fighting in foreign wars. I didn't know who said it, or why. I nearly jumped out of my chair when I found out that it referred to Shays' Rebellion. Thomas Jefferson wrote those words to support a domestic tax riot! If there's a better example of a radical populist notion being used exclusively by conservative hawks, I'm not aware of it.
Page 241 of Thomas Jefferson: an intimate history by Fawn McKay Brodie (which, hopefully, you can see below) gives the entire quote along with some details on Jefferson's reaction to the French Revolution. It's quite an eye-opener.
