I hold it that a little rebellion now and then is a good thing, & as necessary in the political world as storms in the physical. Unsuccessful rebellions indeed generally establish the incroachments on the rights of the people which have produced them. An observation of this truth should render honest republican governors so mild in their punishment of rebellions, as not to discourage them too much. It is a medecine necessary for the sound health of government.

Thomas Jefferson (1743-1826) American political philosopher, polymath, statesman, US President (1801-09)

Letter to James Madison (30 Jan 1787)
    (Source)

Referring to Shays' Rebellion. See his contemporaneous letter to Abigail Adams.