in the book unwind, how would the world change if it was outlawed

The question is a bit unclear. I believe that "it" refers to the process of unwinding. In the book, unwinding can be done on a teenager as a form of retro-active abortion. The child's body parts and organs are completely harvested and donated to other people. The book's introduction states that this process appeased the demands of the people that are opposed to abortion as well as the people that are for abortion.

The Second Civil War, also known as "The Heartland War," was a long and bloody conflict fought over a single issue.
To end the war, a set of constitutional amendments known as "The Bill of Life" was passed.
It satisfied both the Pro-life and the Pro-choice armies.

Apparently, the debate between Pro-life people and Pro-choice people got so heated and so critical that an entire war was fought over which belief system should be put into place. If the "Bill of Life" was repealed, the process of unwinding would stop. It is likely that the debate would once again rage, and another war would probably follow.