"In order to form a more perfect union" is a direct quote from the preamble of the U.S. Constitution that helps establish the purpose of the document. Prior to its independence, the United States was still a union of states, but "in order to form a more perfect union," the Constitution was created.
An update to the Articles of the Federation, the Constitution established the new federal powers of the United States as an independent nation. James Madison and Gouverneur Morris were the primary authors of the U.S. Constitution. The writing of this document took place at the Constitutional Convention in 1787, where representatives from all of the states met in order to ensure the most comprehensive agreement among the Union. Ultimately, the Constitution favored a strong federal government, and James Madison later teamed up with Alexander Hamilton to write the Federalist Papers, which were a series of essays that the authors intended to use to generate popular support for the Constitution.
George Washington was the first U.S. president, and he was the first to operate under the stipulations of the U.S. Constitution. Since its establishment, the Constitution has been amended 27 times. The first 10 amendments comprise the Bill of Rights.