The Founders wanted to add the Bill of Rights to the Constitution because they wanted to include a way to amend the Constitution.

The Founders wanted to add the Bill of Rights to the Constitution because they wanted to ensure that people’s rights were protected.

Explanation:

The Bill of Rights was proposed following the long debate over ratification of the U.S. Constitution (1787–88). At the time several states deemed necessary the creation of amendments that specifically protected individual rights from abuses of the federal government that weren't stated in the Constitution.

The bill of rights, consisting of 10 amendments, lists specific prohibition on government power and liberties of people, for example, people's right to enjoy a speedy and public trial by an impartial jury of the state in criminal prosecutions, freedom of religion, the right to be free from unreasonable government intrusion in their homes through the requirement of a warrant, among others.

would not cooperate with each other voluntarily.