In the early years of the United States, there was much debate over how to handle the admission of new states into the union. One proposal that was put forward was to admit new states in pairs, with one free state and one slave state being admitted at the same time.
This proposal, known as the „Twin Pairs” plan, was put forward in the early 19th century as a way to maintain a balance of power between free and slave states in the US Senate. Under this plan, every time a new free state was admitted, a new slave state would also be admitted, and vice versa.
The idea behind the Twin Pairs plan was that it would prevent either the free or slave states from gaining a permanent advantage in the Senate. Each pair of states would cancel out each other`s votes, keeping the balance of power between the two sides.
Although the Twin Pairs plan was never formally adopted, it did influence the admission of new states during the 19th century. For example, when Maine was admitted to the union as a free state in 1820, Missouri was also admitted as a slave state, in order to maintain the balance of power in the Senate.
However, as the slavery issue became more contentious in the years leading up to the Civil War, the idea of admitting new slave states became increasingly unpopular in the North. This led to the eventual adoption of the „free soil” policy, which advocated for the admission of only free states to the union.
Today, the Twin Pairs plan is an interesting historical footnote in the ongoing debate over how to admit new states to the union. While it may have been a practical solution at one point in American history, it ultimately proved to be unworkable in the face of changing political realities.