Short answers, pulled from the story.
Gouverneur Morris, a Pennsylvania delegate, led the Committee on Style which wrote this final draft without prior discussion on the convention floor. Jacob Shallus engrossed the handwritten copy of the document in 1787.
The brief introductory statement was placed into the final document during the last days of the Constitutional Convention held at Independence Hall in Philadelphia. The handwritten copy was engrossed by Jacob Shallus in 1787.
Courts have consistently ruled that the Preamble serves solely as an introduction and does not assign powers to the federal government. Justice Holmes stated in Jacobson v. Massachusetts decided in 1905 that the preamble indicates general purposes but has never been regarded as the source of any substantive power conferred on the government.
Sovereignty remains with the people by whom and for whom all government exists and acts as affirmed in Yick Wo v. Hopkins decided in 1886. The Supreme Court in Chisholm v. Georgia in 1793 declared that the people exercised their own rights and proper sovereignty when establishing the Constitution.
The phrase explains the nature of the governmental entity created by the Constitution and establishes that the United States consists of only one sovereign nation with respect to foreign affairs. Individual states may not conduct foreign relations even though each state was originally recognized as sovereign unto itself.