Necessary and Proper Clause

In construing this clause it would be incorrect and would produce endless difficulties, if the opinion should be maintained that no law was authorized which was not indispensably necessary to give effect to a specified power. Where various systems might be adopted for that purpose, it might be said with respect to each, that it was not necessary because the end might be obtained by other means. Congress must possess the choice of means, and must be empowered to use any means which are in fact conducive to the exercise of a power granted by the constitution.