At what point is overthrowing a government ethical, considering all the violence a revolution usually entails?

Here's a thought :


" We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.

" That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed,

" That whenever any Form of Government becomes destructive of these ends, it is the Right of the People to alter or to abolish it, and to institute new Government. "