The idea is to use select states to test the viability of all laws that aim to solve problems (gun deaths), change behavior (texting while driving), or achieve goals (better education).
This will provide federal legislators with evidence of usefulness over the course of a trial period. It will provide incentive to craft legislation that can be tested. Finally, and perhaps most importantly, it will prevent bad laws from messing up the entire country.
The idea goes something like this:
When a law is passed, not less than three and no more than ten representatives involved in the the bill and/or voted for its passing must hold a trial of the law in their state. Of those who voted against the bill, a matching number of representatives will devise a system to test the law's effectiveness.