Congress is made up of 535 men and women (100 Senators and 435 Representatives), each performing a delicate balancing act between the needs and demands of their constituents, their political parties, their contributors, their staffs, the Administration, and even each other. These often conflicting demands can simultaneously pull members of Congress in dozens of different directions on any one issue. It is against this background that legislative process, or the passage of a bill into law, occurs in the two Chamber's of Congress.
Congress is collegial, not hierarchical, and power and influence in administration decision making tend to flow in all directions. Although the How does a Bill become Law? chart is useful in understanding the general legislative process, it is not a defined roadmap. Since no two bills ever follow exactly the same path to enactment, you always have to rethink the chart with every bill you research, keeping in mind the parliamentary and political maneuvering that can occur anywhere in the process.