My apologies if this has been around the block a few times, but what would happen if Quebec joined the American Revolution, perhaps because Benedict Arnold carried a few copies of the Declaration of Independence in French with him? I think the presence of French-speaking delegates to the Constitutional Convention would make the Constitution, and American legal language by extension, have a greater degree of French influence in style. And when French people saw that the people of Quebec could work well under a Republic, perhaps they would have come to deposing Louis XVI earlier.