Answer: Article 1, section 9 clause 1. It deals with the issue of importation of slaves.
Explanation: Article 1 section 9 clause 1 places restrictions on the powers of congress in regards to slave trade. This clause prevented Congress from stopping or limiting the importation of slaves before 1808. However, it allowed Congress to levy a tax of up to 10 dollars for every slave. Although the international slave trade was stopped in 1807 and no more slaves were allowed to be imported legally into the United States, slavery was still legal within the United States until the end of the Civil War when the 13th Amendment was passed in 1865.
