On May 10, 1776, the Continental Congress directed all of the colonies adopt new written constitutions. Between the years of 1776 to 1783, each of the thirteen former colonies would draft and approve their own state constitutions. Many of the states responded to their experiences with the overbearing executive authority of the British Crown and their dislike of Parliament by creating powerful unicameral state legislatures. These bodies proved to present a number of issues in practice: they were too easily controlled by one faction or another, they often invalidated actions of the governor or the judiciary, and they were prone to pursuing short-sighted agendas. In many cases, state governments became unstable as a result. A bicameral legislature, on the other hand, made the legislative process more deliberate. By 1787, when the Constitutional Convention met, all of the states except Pennsylvania and Georgia had divided their legislatures into two houses, suggesting that most of the delegates considered the bicameral legislature one of the best devices for making the lawmaking process more deliberative.
Benjamin Franklin, who had helped draft the Pennsylvanian Constitution, was the only Framer who seriously advocated a unicameral legislature in the Constitutional Convention. Not only did he fail to garner much support in the Federal Convention for a unicameral legislature, but even Pennsylvanians would see the error of their ways just three years later and adopt a bicameral legislature for themselves. Georgia also adopted a bicameral legislature shortly after the Constitution was adopted. Experience proved, time and again, that bicameral legislatures were superior, and their benefits were compounded when each house had a distinct character.
In some respects, the ultimate preference for two houses in the legislature was rooted in the precedent set by Britain’s Constitution, but America’s version also differed in important respects. The British example (as well as the theories expounded by Enlightenment philosophers such as Locke and Montesquieu) presupposed the ancient conception of the mixed regime, a blending of democratic, aristocratic, and monarchical features. Therefore, the legislative power was divided between an upper house dominated by the rich and well-born (the House of Lords) and a lower house controlled by the people (the House of Commons). Dividing the legislature in this way reinforced the advantages of a mixed regime: it gave to every special interest in society some portion of power in order to protect itself from other interests.
America, though, was a country that boasted greater equality of condition than any other in history, so the class-based structure of Parliament did not make much sense in the United States. As Tocqueville would later observe, America had been a democratic land even before it was a country. Consequently, all power – whether legislative, executive, or judicial – would have to be derived from the people. But the Framers could nonetheless see that the various mechanisms for dividing power into separate and distinct hands remained a prudent safeguard for the people’s rights. They would therefore have to find a way to do what the British had done without relying on the mechanism of the mixed regime – divisions between the people, the nobility, and the monarchy – to reinforce the separation of power.