Because it protects the second amendment, and clarifies that guns can be used only for lawful purposes (like hunting, or self defense in home)
Sources are used in a paper to show what ideas inspired you and whose theories you would be using and you cite the sources in order to avoid plagiarism. If you don't have sources, your paper will not be valid and you could get accused of plagiarism. The more sources you use the better but you should keep in mind that they need to be important for the paper and used with a purpose and not just to increase the number of sources.
Churchill led England during World War 2!
