The Preamble does not confer power, but its first words, "We the People of the United States," describe the source of the powers conferred by the rest of the Constitution and have been used by the advocates of a strong union arguing against the proponents of states' rights. The Preamble also states the purpose of the document. One of the statements of purpose, "to … promote the general welfare," has been of great importance in the 20th cent. in upholding social legislation, for which no warrant could be found in the enumerated powers of Congress.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.