The United States has experimented with several different constitutions for adding states. Of all of these regimes, the shortest lived was also the one selected by the Federalist drafters of the Constitution. Under this regime, Article IV, Section 3 bestowed on Congress broad power to govern new territories as colonies of the original states, allowing Congress to place any conditions that they pleased on their admissions. This regime was created by Federalists, like Gouvernour Morris, who were suspicious of Scots-Irish frontiersmen and eager to settle western territory using land companies who would insure that new settlers were deferential to Federalist leadership back east and loyal to the national government. Whatever its merits in terms of text and original understanding, however, the Federalist constitution of company towns was quickly supplanted by a constitution of popular sovereignty. Initially devised by the Northern Democratic Party between 1845 and the Civil War to overcome intraparty divisions over slavery, the Republican Party preserved the basic structure of popular sovereignty after the Civil War to become the unwritten constitution for adding states today. Our national experience with the constitution of state admissions is that cross-partisan constitutional conventions, not text or original understanding, are the real foundations of durable constitutional rules.
Roderick M. Hills Jr.,
The Unwritten Constitution for Admitting States,
89 Fordham L. Rev. 1877
Available at: https://ir.lawnet.fordham.edu/flr/vol89/iss5/8