Looking at the source on McCain's store site, we see how much his campaign cares about minor things like honesty and other people's copyrights.
<div id="footer_bottom" style="visibility:hidden">
VOLUSION LINK - BEGIN
Customer has agreed per Volusion’s Terms of Service
to maintain a text hyperlink to "http://www.volusion.com" in the
footer of the website. The link must be standard html, contain no
the Volusion agreement.
<p>Shopping Cart Powered by <a href="http://www.volusion.com"
title="Shopping Cart Software" target="_blank">Volusion</a>.</p>
For those who don't speak html, he's hiding the required visible link.