Final answer:
State constitutions appeal to policy advocates because they are more adaptable, can be influenced through various processes, and serve as experimental grounds for policies that may later influence national policy.
Step-by-step explanation:
Policy advocates often find it easier to shape national policy by first shaping state constitutions because state constitutions are seen as more malleable and accessible, they often serve as a testing ground for policy innovations. Advocates start with an objective and create proposals to accomplish specific goals, utilizing facts and analysis to gain support. Additionally, each state has a different process for changing its constitution, with some allowing voter-led initiatives and others being controlled by the state legislature, making it logistically appealing to policy advocates to focus efforts at the state level where there might be fewer barriers to change compared to the national level. Furthermore, as noted by Supreme Court Justice Louis Brandeis, states have the ability to act as "laboratories" for new policies which can be adapted and adopted at the national level later on. This is particularly effective in a federal system where state diversity allows for a range of policy approaches. Lastly, constitutions are foundational documents that outline the basic structure and are crafted with a deliberation reflecting durability and the setting of political principles that are intended to be long-lasting, thereby creating an impactful avenue for policy innovators.