This paper identifies a problem that constitutional amendment uniquely poses for originalist theories of constitutional interpretation, namely: how to reconcile changes to a constitution's text that enact a new set of understandings ('amenders' understanding') against the understandings of the constitution's framers ('original understanding'). This problem presents a significant challenge for originalism that has largely been neglected by scholarship to date. The paper addresses this lacuna. First, it will clarify the nature of the problem by identifying the circumstances under which it arises. Second, it will evaluate possible originalist responses. In particular, it will consider whether there is a response available that would make originalism more attractive than other efforts to prescribe limitations on the power of an amendment to override original understanding, such as 'basic structure' and 'unconstitutional constitutional amendment' type doctrines.