The correct answer to this open question is the following.
Unfortunately, you forgot to include the excerpt to know what you are talking about.
Although you did not include the excerpt, the name of the text, or the author, we can do some research and help you with the following general comments.
One historical event in the period 1787 to 1803 that would be used to support Ellis's interpretation is the United States President Thomas Jefferson's historical interpretation about the approval of the Louisiana Purchase.
For historian Joseph J. Ellis, the issue was the way President Thomas Jefferson proceeded to buy the Louisiana territory to the French, knowing that he could have been going beyond his powers as the head of the executive branch. The question for historian Ellis is not that his decision over the territory was right, but the way he implemented that decision that challenged his powers as President. Thomas Jefferson had big hopes that the next step for the American government was in the conquest of the western part of the United States.