Source: "Brutus" Letter XVI April 10, 1788, "John DeWitt" Letter III Nov. 5, 1787, Anti-federalists Papers

They uniformly exercise all the powers granted to them, and ninety-nine in a hundred are for grasping at more. It is this passionate thirst for power, which has produced different branches to exercise different departments and mutual checks upon those branches. The aristocratical hath ever been found to have the most influence, and the people in most countries have been articulately attentive in providing checks against it. Let us see if it is the case here. -- A President, a Senate, and a House of Representatives are proposed. The Judicial Department is at present out of the question, being separated excepting in impeachments. The Legislative is divided between the People who are the Democratical, and the Senate who are the Aristocratical part, and the Executive between the same Senate and the President who represents the Monarchial Branch. -- In the construction of this System, their interests are put in opposite scales. If they are exactly balanced, the Government will remain perfect; if there is a preponderancy, it will firmly prevail. When great and extraordinary powers are vested in any man, or body of men, which in their exercise, may operate to the oppression of the people, it is of high importance that powerful checks should be formed to prevent the abuse of it.

In the Anti-federalists papers, the letters dated in 1788 and 1787 argued two points. The two points were:
1)
2)

I'll be glad to comment on your answers.

1) The first point argued in the Anti-federalists papers, specifically in "Brutus" Letter XVI dated April 10, 1788, and "John DeWitt" Letter III dated Nov. 5, 1787, is that those in power consistently seek to expand their powers. The authors claim that those in positions of authority always have an insatiable thirst for power and attempt to extend their reach beyond the limits granted to them by the people. They argue that this hunger for power necessitates the establishment of checks and balances to prevent its abuse. These checks and balances include the division of powers among different branches, such as the legislature, judiciary, and executive, as well as the articulation of specific limitations on their authority.

2) The second point argued in the Anti-federalists papers is the concern about the imbalance of power within the proposed system of government. In the passage, the authors mention that the legislative power is divided between the democratic branch (representing the people) and the aristocratic branch (representing the Senate). Furthermore, they point out that the executive power is also divided between the Senate and the President, who symbolizes the monarchical branch. The authors express worry that if there is a noticeable imbalance of power favoring one branch over the others, it could result in the oppression of the people. Hence, they emphasize the importance of establishing powerful checks to prevent the abuse of authority and maintain a balanced government.