We called our Articles of Incorporation (for IRS 501c3 purposes) a Charter, partly because the IRS documents specifically state that "by-laws by themselves may not pass the Organization Test" (paraphrase).
Our Charter is a high-level document that states in mostly broad-brush terms that we exist as a organization and how we are organized and operate. It takes a 2/3 majority to amend the Charter.
We have not generated a more detailed document that we would call by-laws, but the Charter implies we should, especially in that the Charter does not specify what Committees we have (just that there will be committees and describes how they operate). The idea is that the details could change (fundraisers come and go) so the by-laws could change easily (majority vote), but the controlling document (the Charter) stays constant.
I agree it is easier to keep it all in one document, but there may be valid reasons to keep an obsolete practice.
You only need one set of bylaws, so go ahead and combine the constitution and bylaws. I found this quote in a book I have about Robert's Rules by D. Patnode, "Some organizations insist on having two chief documents, the constitution and the bylaws; but such practice is obsolete, inconvenient, and potentially dangerous. There should only be one chief document, normally called bylaws."
That said, if you incorporate (encouraged), you will need to draft Articles of Incorporation which essentially declare your organization exists. The specific content is defined by your state in the application for incorporation (and by the IRS), but it most likely doesn't overlap with the detailed articles of your bylaws. In our case, we have AOI to fulfill our legal requirements, but operate according to our bylaws.
We are trying to revise our very old and ineffective by-laws. The problem is that we also have a constitution. After reviewing other catholic school by-laws in our area, they don't have a constitution. All their information is mentioned in their by-laws. We have all the same articles except they are split between our by-laws and constitution, some articles are even duplicated. That's just more to read! Can I rid the constitution and just revise it all in our by-laws?
