WHY bicameral legislation?

Answer 1

The US Bicameral legislature is chiefly to balance the power of large states with small ones.

Both the house and senate have to pass bills before they can become law. In the House of Representatives, representation is by population. So large states have more reps in congress than small ones. In theory, a few large states can muscle through bills in the house that benefit them and leave the small states out. But in the senate, each state has two senators no matter what the population so each state has an equal vote. Since both houses have to agree on a bill before it goes to the president, there is little chance that a bill unfair to smaller states can pass.

So it's part of the checks and balances of our system to ensure that the majority cannot unfairly treat the minority.

Answer 2

It's part of the system of checks and balances the framers of the Constitution set up.

The theory is this: The Senate and the House are ccomposed of two more or less seperate groups--with the House, because of its proportional representation and 2-year terms, effectively required to be more responsive to the popular will; the Senate tends to be more of a deliberative body because it is more independant of short-term issues and passions.

A bill, to pass, has to pass both houses of Congress. This makes it much more likely that proposed laws will be well-thought out or at least throughly debated.

The system works fairly well--though obviously its far from perfect. But so far, no one in human history has come up with a better system.