Child Pages Not Nesting

I’m trying to build a vertical nested nav bar and have been unsuccessful in sorting out why my child pages aren’t nesting under their appropriate parent pages.

The mostly generic wp_list_pages subpage code I’m using:

<div id="pagenav">
<ul>
<?php if($post->post_parent)
$children = wp_list_pages("title_li=&child_of=".$post->post_parent."&echo=0"); else
$children = wp_list_pages("title_li=&child_of=".$post->ID."&echo=0");
wp_list_pages("title_li=&depth=1&exclude=2");
if ($children) { ?>

<?php echo $children; ?>
</ul>
</div>

<?php } ?>

The children of the current page show up underneath all of the page items. This site currently lives at stlukes.dreamhosters.com. View a specific example at https://www.stlukes.dreamhosters.com/christian-education/ and notice the children show up after “Contact Us.” I’m sure I’ve overlooked some simple detail. Blarg!

I’m fairly well versed with WordPress, but I’m a newb to PHP. Please be gentle!