He thought that firstly no document or law could be forever relevant, so it needed revisioning occasionally, and the 19 years seems to tie into the idea of each generation taking a new look and either accepting existing laws as still good or making changes.
19 years, in a letter from Jefferson to Madison.
To James Madison from Thomas Jefferson, 6 September 1789
He thought that firstly no document or law could be forever relevant, so it needed revisioning occasionally, and the 19 years seems to tie into the idea of each generation taking a new look and either accepting existing laws as still good or making changes.