Why are most (U.S.) state legislatures bicameral?

Most U.S. states (with the exception of Nebraska - I think the only exception) have a bicameral legislature - similar to the structure of Congress with House and Senate, also similar to the British Parliament with its Houses of Commons and Lords. But the representation in state legislatures seems to be geographic - you get to vote for a State Assemblyman in the Assembly district your home is in, and you get to vote for a State Senator in the Senate district your home is in.
Why is that? It seems inefficient to me, compared to two possible alternatives:

  • Have one house of the legislature be geographically-based, and the other be proportionally-based (probably state-wide)

  • Have just one legislative body, like in Nebraska or what Puerto Rico will be soon
    How did it get to be that way? I’d be interested in both the historical story (were competing proposals - if there were any - shot down somehow?) or in the theoretical justification.
    [sub]Mods, I realize this might be a topic not well suited for GQ… but I’m not really interested in a debate, maybe IMHO if this should be moved?[/sub]

I don’t have an answer to your question, but a minor nitpick. Here in South Dakota, what you call an ‘Assemblyman’, we call a Representative just like the feds do. Therefore , we have a state House and state Senate, not a state Assembly.

I seem to remember learning that, years ago, most states had an upper house set up like the Senate, with each county selecting a member. As in the Senate, this made sure that the more sparsely-populated counties didn’t get totally ignored. However, the Supreme Court ruled this was unconstitutional. How a legislative scheme directly modeled after the US Constitution could be unconstitutional was not clear to me, and frankly this ruling strikes me as being rather profoundly retarded.

This is right. The case is Reynolds v. Sims (1964). The Court found that state legislatures were elected for the purpose of representing the people and therefore must be apportioned equally among the population. Previously, many states had systems where an upper house was composed of members representing individual counties which may vary greatly in population.

There’s a difference. The US Constitution sets up a federal republic in which the interests of both the people (the House) and the states themselves (the Senate) are to be represented. The US Constitution also charges the federal government with ensuring that every state be guaranteed a “Republican Form of Government.”

The Justices could not reconcile the unequal representation of citizens in state legislatures with the ideal of republicanism. That decision therefore eliminated unequal apportionment in state legislatures (as well as municipal governments). Even if they wanted to (which they probably didn’t) the Court could not change the structure of the US Senate since the Constitution itself determines the structure.

Diceman is correct. State legislatures were often modeled on the federal plan, with the lower house being apportioned by population, and the upper house different (e.g., by county.) In the 1964 case Reynolds vs. Sims, the Supreme Court ruled that ALL legislative districts had to be based on population.

How could, as Diceman asks, a state go wrong by modeling its legislature after the Federal government? The court’s logic is thus:

The Constitution describers how the House and Senate are designed. (Therefore, it’s “constituitional.”)

The Constitution does not describe how state legislatures should be designed.

The 14th Amerndment, however, DOES say “nor shall any state deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws.”

The Supreme Court ruled that, since the citizens in unpopulous county A had the same number of state Senators as the citizens in very populous county B, that the states were depriving B residents of equal protection called for by the 14th Amendment.

Your interpretation of the 14th Amendment may be different.

I haven’t seen the simple answer here: having two bodies, one that is proportional to regional population and one that is strictly region-based, ensures more equal representation overall. One or the other means that either urban areas or thinly-populated regions have disproportionate representation.

Some historic perspective on why the Constitution calls for two houses.

After this argument was won on the national level it was almost inevitable that the state governments would follow the same logic. Nebraska didn’t become unicameral until 1937 and did so largely to cut costs in the Depression.

Two other aspects of the decision:

  1. The states are not themselves federations, unlike the United States as a whole, and therefore the analogy to the federal Congress did not have any weight.

  2. The equal protection argument was not merely theoretical. By the time of the decision, the black population in that state was largely concentrated in urban areas, while the rural areas were sparsely populated with a white majority. That meant that even if anti-Jim Crow measures passed the state Assembly, the state Senate would reject them. The net effect of equal county representation in the state Senate was to perpetuate Jim Crow laws, even if there was popular support to change them.

Bcameral legislatures long predate independence. The British set up bicamerals in 10 of the 13 colonies (the exceptions were PA, DE, and GA) partly in imitation of their own Parliament and partly to protect royal or proprietor power; the upper house would usually be appointed and the lower elected.

With independence the colonies with bicamerals retained them, and DE and GA adopted them. (Pennsylvania retained a unicameral in its constitution of 1776, but went bicameral in 1790. The vote in the 1789-90 constitutional convention was 56-5 in favor of bicameral. I’m not sure as to what arguments were advanced. With that lopsided a vote not many arguments were necessary.)

The main reason for retaining bicamerals upon independence was elite fear of mob rule. The upper house would no longer be appointed, but would be more aristocratic and insulated from popular passion by some combination of the following:[ul]stricter property qualifications for senators[/ul][ul]stricter property qualifications for suffrage in senate elections[/ul][ul]larger districts for senators[/ul][ul]more geographic and less population-based districts[/ul][ul]longer terms for senators[/ul]Over time, of course, property requirements went out of fashion, so the first two bullets vanished. And as noted the fourth bullet was ruled unconstitutional by the Supreme Court. So today only the third and fifth points serve to distinguish the two houses.

Note that Vermont, which patterned its constitution after Pennsylvania, went unicameral in its constitution of 1777, was admitted to the Union as such in 1791, but went bicameral in 1836. I am unsure of the reasons. After that no state went unicameral until Nebraska in modern times.

Unless I’m misunderstanding, that’s not quite true here in South Dakota. We have 35 legislative districts and elect 2 Representatives and 1 Senator from each so, I think, our legislature is all region-based.

The supreme court said that people have interests; land does not. I fail to see how giving urban areas their fair share gives them disproportionate representation. By definition it gives them fair representation.

In Penna, there were two other factors. The state constitution simply declared that no county (Philadelphia was coterminous with its county) could have more than a certain percentage (I forget the exact figure) of state representatives. Second, they had refused to redistrict since, IIRC, 1900 despite the great growth of Philly and Pittsburgh between then and 1964. And the state legislature was totally dominated by rural representatives so the situation could not change so long as the courts refused to enforce the constitution of the commonwealth. And both the state supreme court and the national one had, for decades, refused to get involved.

It’s not a matter of “land having interest.”

A person in a city with several hundred people per square mile and a person living in a rural area - particularly a farming region - with a handful of people per square mile have very different representational needs. A system that represents the citizens by more or less equal population groups will end up shortchanging people in lightly settled regions; a system that represents people by equal regional sizes will tend to screw those in the denser ones. So a bicameral system that represents the population from both directions has a better chance of representing them all more favorably.

Because they’ve always done it that way.

That’s not disproportionate, but it doesn’t matter because that’s not how state legislatures work. “Region-based” legislatures have been illegal for half a century.

Freddy the Pig’s answer is on point as usual. (Though the colonial council of Georgia did participate in legislation meaning it wasn’t unicameral.) Regarding the Pennsylvania constitution of 1790 there really wasn’t much left to say that hadn’t already been said during the long struggle to replace the unicameral revolutionary constitution or during the ratification of the federal constitution which technically was still ongoing. Pennsylvania actually ratified its new constitution in February before Rhode Island finally ratified the federal constitution on May 29, 1790. The state convention took a couple months to work out the details of its new constitution (you can find a link to a PDF of the minutes here) but its bicameralism was never in doubt. The supporters of the original state constitution had lost that fight when the reformers were able to have their call for a constitutional convention widely accepted despite the fact that it was illegal.