• Congress has two chambers: Senate and House of Representatives
• Senate is smaller; each state has two senators
• House is larger; each state has a number of representatives proportional to its population
• Founding Fathers chose bicameralism for historical, theoretical, and practical reasons

The Constitution created a bicameral national legislature—that is, a Congress composed of two separate chambers, the Senate and the House of Representatives.

The Senate, sometimes called "the upper house," is smaller (currently 100 seats) and its members serve longer terms (six years). Each state, no matter how large or small, has equal representation (two seats each) in the Senate.

The House of Representatives, a.k.a. "the lower house," is much larger (currently 435 seats) and its members serve much shorter terms (two years). Representation in the House is proportional to population, so larger states receive many more seats than do smaller states.

Both houses have certain unique powers and responsibilities, but for the most part, the House and Senate work in parallel. That is to say, senators and congressmen perform broadly similar functions in the national government. Both houses have to pass any piece of proposed legislation for it to become law. The House and the Senate are arguably redundant institutions.

Why, then, did the Constitution create a bicameral legislature? Why not merge the House and Senate into a single unicameral legislative body?

There are three main reasons.

The first was a matter of historical precedent. While the American colonists had rebelled against British rule in the Revolutionary War, they still drew many of their ideas about government from their colonial experience as British subjects. And the British Parliament had two houses—an upper chamber, the House of Lords, filled with representatives of the aristocracy, and a lower chamber, the House of Commons, filled with representatives of the ordinary people. That example shaped the thinking of the Constitution's framers.

The second was more theoretical. The framers' emphasis on the idea of checks and balances led them to be suspicious that a unicameral legislature might consolidate too much power in one institution. By dividing legislative power between the House and the Senate, the two chambers would serve as checks against each other's authority, theoretically preventing either from ever gaining tyrannical power.

The third, and by far the most important, was a matter of practical politics. The Constitutional Convention included delegates from twelve of the original thirteen states. (Rhode Island boycotted the whole thing.) Those delegates came from small states and large states. The small states, afraid of losing influence in the new government, demanded that representation in Congress be awarded on an equal basis to all states, no matter how large or small. But the large states insisted, no less forcefully, that representation should be based on population; since larger states had more voters, they ought to have more votes in Congress, too. This fierce dispute over representation dragged on throughout the summer of 1787, threatening to derail the entire Constitutional Convention. But a bicameral legislature provided the perfect opportunity for compromise—in fact, for "The Great Compromise." Small states got their equal representation in the Senate, large states got their proportional representation in the House, and everyone went home happy.

But was "The Great Compromise" really so great? If the first principle of democracy is "one person, one vote," then how democratic is the United States Senate? Today, the largest state (California, home to more than 36.5 million people) has a population about 73 times larger than the smallest state (Wyoming, home to just over 500,000). But the two states' representation in the Senate is equal—two seats each. That arguably means that an individual voter from Wyoming is worth 73 times as much as any one Californian. Is that fair? Is that democratic? (Your answer to that question will probably depend on whether you live in Cheyenne or San Francisco.) On the one hand, the current system does ensure that places like Wyoming aren't entirely ignored in our national politics. On the other hand, it hardly seems fair to deny Californians (and Texans, New Yorkers, and residents of other large states) the right to "one person, one vote."

Whatever you think about the justice of equal representation in the Senate, the system is here to stay. Article V of the Constitution guarantees that no state can ever be stripped of its equal representation in the Senate without giving its consent...and Wyoming is no more likely to agree to that now than the small states were back in 1787.

So if you don't like the current setup, maybe you should just move to Canada. Or Wyoming.