I just learned something. If you start a post and don't publish it, and then do another one on a different subject, and then go back and finish the first one and publish that, the post that you published second will be below the one you published first, because it's saved under the date you started it, and Blogger won't let you change the date. Bizarre. Obviously the people who built Blogger value linear thinking.
There. Now it's in the right order.