Two political bodies and the president have to agree to pass a law, which partially explains why so few pass. Introducing a bill is easy, and some politicians will introduce a bill to make a point. Many bills are withdrawn.
Comprised of 535 people, Congress is a large political body, and those who are elected have certain policies they promised to work for. As a result, politicians often feel that they have to introduce legislation to keep their constituents happy. Even if a particular piece of legislation has no chance of succeeding, a politician might propose it to express support for an idea.
Bills also have to navigate through various committees in order to be voted on, and many bills die before they even come up for a vote. During committee discussions, some bills may be ignored entirely. It is up to sponsors to push for their bills to gain attention.
Even though only 5 percent of bills become law, politicians often use amendments and larger pieces of legislation to accomplish the same goal. During negotiations, politicians will often agree to vote in favor of a bill if their legislation is included as an amendment. Amendments do not have to be related to the bills to which they are attached.