5th grade history.
http://www.scholastic.com/teachers/article/explaining-bill-rights
When the delegates sought to have the new Constitution ratified, they faced a similar problem. They thought everyone knew what individual rights were, so they did not define them in the Constitution. However, the lack of specific guarantees of personal liberty was one of the main reasons why a number of states were reluctant to accept the Constitution.
Objections to the Constitution
In order to approve the new Constitution, voters were to elect representatives to special state conventions. In New York, Virginia, and Massachusetts, the people and their representatives were strongly opposed to the Constitution. They were called the "Antifederalists." The Antifederalists included such patriots as Patrick Henry, the Virginia orator; Sam Adams, the Massachusetts agitator; George Mason, who had written much of the Virginian Constitution; and Richard Henry Lee, who had served as Virginia's delegate to the Continental Congress.
The Antifederalists argued that the states would be absorbed into an all-too-powerful national government. They claimed that the limits on direct voting and the long terms of the president and senators would create an aristocratic class. They also feared that the president might become another monarch. In other words, these Antifederalists felt that the new Constitution was most undemocratic.
Their major objection to the new Constitution was its lack of a bill of rights.
"Bills of rights" list the specific freedoms that governments cannot threaten or take away. When the Constitution was being written, many state constitutions already had bills of rights. For that reason, the authors of the Constitution did not feel it was necessary to have another one.
The antifederalists believed that without a list of personal freedoms, the new national government might abuse its powers. They worried that it would destroy the liberties won in the Revolution.
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The Ninth and Tenth Amendments: Reserved Powers
The last two amendments address the liberties of citizens and the rights of states. The Ninth Amendment states that the Constitution and the Bill of Rights do not define all of the fundamental rights people have. Such rights exist whether or not they are defined. The Tenth Amendment makes a similar claim concerning the rights of the states. It holds that the states and the people have powers that are set aside and not listed item by item. These powers are called "reserved powers." They can be contrasted with "express powers," which are specifically defined in the Constitution.
In this way the Constitution allows for growth and change.
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The right of the citizens to keep and bear arms has justly been considered, as the palladium of the liberties of a republic; since it offers a strong moral check against the usurpation and arbitrary power of rulers; and will generally, even if these are successful in the first instance, enable the people to resist and triumph over them.
-- Associate Justice Joseph Story, appointed by James Madison, served 1812-1845, on the 2nd amendment