(see update below) More precisely, Tillman argues here that any attempt to disqualify former Secretary Clinton from the presidency based on conviction of a crime, including 18 U.S.C. § 2701 (which provides that anyone convicted “shall forfeit his office and be disqualified from holding any office under the United States”), would be unconstitutional. FWIW, I think he is right.
Now if Clinton were to be elected to the presidency while actually serving time in prison, a different set of issues would be presented. But I think we can cross that bridge when we come to it.
(Clarification: Tillman does not believe that section 2701’s disqualification language is unconstitutional, but he believes it would be unconstitutional if it were intended to apply to the presidency and other elected positions. In part for this reason, he would interpret the “office under the United States” language as not applying to elected positions).
Update: former Attorney General Mukasey, to whom Tillman was in part responding, has emailed Professor Eugene Volokh to acknowledge “on reflection, … Professor Tillman’s [analysis] is spot on, and mine was mistaken…. The disqualification provision in Section 2071 may be a measure of how seriously Congress took the violation in question, and how seriously we should take it, but that’s all it is.”