One Crucial Issue in Pledge Case: What Does "Under God" Mean?

In addition to this key question -- which Linda Greenhouse's article in today's NY Times summarizes nicely -- there is a tricky little standing question as well. Seems Michael Newdow, the plaintiff, isn't married to the student's mother and isn't the custodial parent, either. So does he have standing to sue the school district to stop the pledge? The briefs make fascinating reading (for students of standing law): petitioner school district, United States, Mike Newdow.