Franklin had little to do with the first drafting of the document, which the committee left to Jefferson, partly because of his known felicity of phrasing (“You can write ten times better than I,” John Adams recalled telling Jefferson), partly because Jefferson was a Virginian (and hence would add geographic balance to a conflict provoked by New England), partly because none on the committee appreciated what a momentous document this would be, and partly because Franklin was happy to leave the task to another.
