Seth Tillman has posted this draft on SSRN.  From the abstract:

This paper discusses the scope of the Constitution’s Disqualification Clause (Article I, Section 3, Clause 7) and the original public meaning of its “office . . . under the United States” language. In a recent paper in this journal, Benjamin Cassady argued that this clause bars disqualified former presidents, vice presidents, and officers of the United States from subsequent election or reelection to the presidency and vice presidency. Here, I take the contrary position: disqualified former presidents, vice presidents, and officers of the United States are not barred from any elected positions, state or federal. Rather, such disqualified former presidents, vice presidents, and officers of the United States are only barred from holding statutory or appointed federal offices. Finally, I address some issues relating to best methodological practices and the use of structural and other intuitionist modalities of interpretation when constitutional text is reasonably clear.