Why that final proofread is important

"...the Constitution establishes a social order, then builds upon that social order to find the general will, and ultimately the document itself functions as a Constitution."

...apparently while writing, at some point my brain decided that since I'm writing about how the Constitution functions as a social contract, the two terms are completely interchangeable. The rare case of a typo not being factually wrong - the Constitution does indeed function as a constitution - but still very, very wrong.