"We have always a right to correct ancient errors and to establish what is more conformable to reason and convenience." -- Thomas Jefferson to James Madison, 1801. FE 8:82
"We might as well require a man to wear still the coat which fitted him when a boy as civilized society to remain ever under the regimen of their barbarous ancestors." --Thomas Jefferson to Samuel Kercheval, 1816. ME 15:41
"[The European] monarchs instead of wisely yielding to the gradual change of circumstances, of favoring progressive accommodation to progressive improvement, have clung to old abuses, entrenched themselves behind steady habits and obliged their subjects to seek through blood and violence rash and ruinous innovations which, had they been referred to the peaceful deliberations and collected wisdom of the nation, would have been put into acceptable and salutary forms. Let us follow no such examples nor weakly believe that one generation is not as capable as another of taking care of itself and of ordering its own affairs. Let us... avail ourselves of our reason and experience to correct the crude essays of our first and unexperienced although wise, virtuous, and well-meaning councils." --Thomas Jefferson to Samuel Kercheval, 1816. ME 15:41
"[Algernon Sidney wrote in Discourses Concerning Government, Sect. II, Par 13,] 'All human constitutions are subject to corruption and must perish unless they are timely renewed and reduced to their first principles.'" --Thomas Jefferson: copied into his Commonplace Book.
"Happy for us that when we find our constitutions defective and insufficient to secure the happiness of our people, we can assemble with all the coolness of philosophers and set it to rights, while every other nation on earth must have recourse to arms to amend or to restore their constitutions." --Thomas Jefferson to C. W. F. Dumas, 1787. ME 6:295, Papers 12:113