The Articles of Confederation contained a provision to allow colonies outside of the United States, including Canada, to join as members of the confederation. The Constitution also allows new states to join the country. One theory underlying the Constitution’s provisions for the addition of new states is that the United States is not supposed to hold land as territory indefinitely and act as a colonial power. Though Congress was given the power to govern territory, territories were to be organized as states and added to the Union when they were ready. At the time the Constitution was adopted, the United States had a vast swath of western territory which was rapidly being settled. The country would continue to conquer and annex property until the current borders of the United States were established.
The Constitution provides few rules for adding states, though there was significant debate in the Constitutional Convention regarding the addition of states and the terms of such admission. The Constitution notes that states can be added to the Union and provides limitations on carving new states from old states and creating states from the junction of two states. The provisions were tested soon after the Constitution was adopted; areas that had previously been claimed by individual states subsequently became states in their own right. For example, Vermont and Kentucky became states in the early 1790s.
A few problems arose in the post-Revolution era concerning territory and states. The United States had to address the untamed Western Territory and had to address the claims of individual states that asserted ownership of swaths of territory that they barely governed and likely could not defend in any serious fashion. Given that the United States was not interested in acting as a colonial government for unorganized territory, there needed to be a process for governing the territory and adding states to the Union, since there was reason to believe that the borders of the United States might grow. The addition of states to the Union from territory that was acquired later – either through purchase or because the states had ceded their claims to the federal government – was all part of the westward expansion of the United States.
One exception to the general pattern of admitting states was the admission of West Virginia to statehood. West Virginia’s admission came in the midst of the Civil War, and it was created from land inside of the borders of Virginia, arguably without Virginia’s consent. The constitutional issues surrounding West Virginia’s admission is a balance between the federal government’s duty to preserve the Union at almost any cost and the possible violations of the Constitution’s prescriptions for admitting new states.
The question of the admission of states to the Union is not finished. The United States still has territories and still administers the District of Columbia. Whether territories such as Puerto Rico and Guam should become states is a question that touches on the old ideas that territories ought to be moving toward statehood and that Congress should not perpetually function as a legislature for territories.
The issue of statehood for the District of Columbia is more complicated. The Constitution envisioned Congress exercising legislative power with respect to a federal district so that the district would not be located inside of the borders of any state. The Framers presumed that any state that provided the quarters for the federal government would have access to special favors, and even a state’s proximity to the seat of federal authority would likely result in preferential treatment. However, as the Constitution has expanded individual rights and has been amended to guarantee the equality of citizens, claims that the residents of the District of Columbia do not have political equality and calls for statehood have become more salient. It is also possible that old concerns that the national capital should not be within a state no longer seem as important to some people. Statehood for the District of Columbia would require a constitutional amendment. Whether that is a good idea or not is a matter for discussion.