From my Googling, it appears as though the default behavior in WordPress is to add paragraphs automatically, but in the HTML view, regardless of what style I choose in the Visual Editor’s style drop-down (paragraph, for example), paragraph tags never appear. I also do not see wpautop() called anywhere in my theme (which I inherited from a now departed developer).
What can I do to set this straight? Adding <p> tags to everything is obviously not going to fly with the content editors.