Amendment tree

A method of visualizing the amendment process on a piece of legislation. First, imagine the bill as the trunk and amendments as branches. House and Senate rules permit only first-degree (an amendment to, or branch on, the bill) and second-degree (an amendment to the amendment or a branch on a branch) amendments. However, in the House, a substitute amendment is considered a first-degree amendment, so technically a total of four amendments can be pending at any given time (an amendment, an amendment to the amendment, a substitute amendment, and an amendment to the substitute).

In the Senate, perfecting amendments (those simply altering language of a bill or amendment) take precedence over substitutes (those both altering language and substituting new text). The amendment tree, then, can have many more branches. For instance, one Senator offers a perfecting amendment to the underlying bill, another Senator offers a second-degree substitute amendment to the first amendment, and at the same time a third Senator offers a second-degree perfecting amendment to the original amendment and a fourth offers a substitute to the second-degree perfecting amendment. (Sorting all this out is one of the reasons the Senate employs a Parliamentarian).