Resolved That it be recommended to the several Assemblies, Conventions and Committees or Councils of Safety, of the United Colonies, immediately to cause all Persons to be disarmed, within their respective Colonies, who are notoriously disaffected to the cause of America, or who have not associated, and shall refuse to associate to defend by Arms these united Colonies
Taking up arms against the US is Treason. That's not even an amendment. Jefferson was writing to a US representative in England reassuring him that the US is strong and the rebellion was "no big deal". That section starts off:
The British ministry have so long hired their gazetteers to repeat and model into every form lies about our being in anarchy, that the world has at length believed them, the English nation has believed them, the ministers themselves have come to believe them, and what is more wonderful, we have believed them ourselves. Yet where does this anarchy exist? Where did it ever exist, except in the single instance of Massachusets? And can history produce an instance of a rebellion so honourably conducted?
and continues
Our Convention has been too much impressed by the insurrection of Massachusetts: and in the spur of the moment they are setting up a kite to keep the hen-yard in order.
The "few lives lost in a century or two" he's talking about are those of the people rebelling.