Traces the history of, and analyzes, the current status of the law on a number of prohibited acts forbidden to the federal government as prescribed in Article I, Section 9, of the United States Constitution. Most of these represent constraints on Congress with the exception of the statement that no money may be drawn from the U.S. Treasury except by appropriation, which increases the power of Congress. The provisions include prohibitions against suspending the privilege of the writ of habeas corpus except in cases of emergency and against passing bills of attainder and ex post facto laws. These prohibitions secure important freedoms for the citizens of the United States. Among the other prohibitions discussed are a delay in stopping the slave trade, forbidding taxes on exports between states, forbidding giving preferences to ports of one state, and forbidding public officers from accepting things of value from foreign countries. Several of these provisions, such as those concerning bills of attainder, ex post facto laws, and the writ of habeas corpus laws are the bedrock of our free society. The provision on the need for appropriations enhances the role of Congress and sets up potential conflicts between it and the other two branches of government, conflicts that might lead to highly significant cases that will help to clarify to doctrine of the separation of powers. A table of cases, bibliographic essay, and an index to enable further pursuit of key topics is included to aid students, legal, and constitutional scholars.