Notwithstanding the 10th Amendment’s stricture that congressional power is limited to those powers delegated to it, Congress has broad legislative powers in a number of areas. However, there are other specific limitations on Congress’ power. Article I notes that Congress cannot pass certain types of laws and that it cannot legislate in certain areas. Specific limitations on congressional power arguably serve to restrict the expansion of Congress’ power. These limitations are meant in some cases to protect liberty. Some of these limitations stop Congress from engaging in practices thought to be inappropriate for a representative legislature. Still others are constructed as limitations on how Congress can conduct business. However, all of these limitations place explicit restrictions on congressional action.
Whereas Article I, Section 8 says what Congress can do, Article I, Section 9 contains specific limitations on congressional power. Some of these help preserve the liberty of individuals. For example, Congress is restricted from passing ex post facto laws that criminalize past behavior. Congress is also barred from suspending the writ of habeas corpus, which would effectively allow detention without review. This limit, however, may be suspended when “in Cases of Rebellion or Invasion the public Safety may require it.”
Article I’s limits on how the Congress can spend money essentially enhances the effective operation of government. This limitation indicates that no money is to come from the treasury unless Congress has appropriated it through law. Given that money must be spent to run the government, this limitation requires that Congress act in a transparent manner before money may be spent.
One limitation on congressional power may appear quirky to the modern reader. The limitation on Congress’ ability to grant titles of nobility seems a fanciful limitation, but it is meant to promote the equal treatment of all citizens. It reflects both a rejection of European aristocratic traditions and an affirmation of the republican nature of our ideals and the spirit of our democracy.
The most controversial limitation in Article I, Section 9 (as well as one of the more curious provisions in the Constitution) was the temporary suspension of a congressional power to curtail the slave trade. Under this section, Congress was barred from prohibiting the importation of slaves until 1808. Additionally, Article V made the ban invulnerable to subsequent amendment. Many of the states at the Constitutional Convention had wanted to ban the slave trade immediately, but South Carolina and Georgia refused to agree to any Constitution that would not allow them at least a temporary right of importation. Congress did ban the slave trade at the very moment it was constitutionally empowered to do so; the law became effective on January 1, 1808.