It is often tempting, or at least convenient, to charge sitting legislatures with the task of constitution writing. These bodies are usually representative and are built to write laws. Why not trust them with higher law too? One concern is the problem of self dealing. One of, if not THE most, important tasks in constitution making is setting the balance of power between the legislature and executive. Can we trust legislators not to put their finger on the scale?
Some early evidence suggests that we can. In a working paper, my co-authors Tom Ginsburg and Justin Blount and I compared roughly 200 consitutions written by sitting legislatures with another 200 written by constituent assemblies dedicated to constitution making. Adapting a measure of legislative power developed by Steven Fish, we found that, if anything, sitting legislatures tend to provide LESS power to legislatures than do constituent assemblies. This finding could very well be a product of non-random selection in distribution of the constitutional process (this is observational data, after all). Nonetheless, the findings should provide some comfort to those who lose sleep at night wondering about self-serving legislators!