Well, that was the right suggestion with one modification. It needed the { and } braces.
What confused me about the 'dual pass', is that I forgot that the jsp:include tag gets translated by the JSP compiler into actual
java code that gets the requestdispatcher etc, etc... and that all three conditions are actually compiled into the
servlet, but of course only one of them gets performed at request-time, based on that variable. I was thinking that the JSP compiler would take the <jsp:include....> tag and turn it into an out.println("<jsp:include...>"); but of course this doesn't happen, because it's outside the <% %>'s.
Thanks for the help.