The answer is yes. Or no, depending on which edition of the Washington Post you read. On Monday, the Post ran an online story entitled “Arizona statute could endanger Giffords’ hold on seat” (which appears to be no longer available on the Post website) explaining that an Arizona statute requires that an office be deemed vacant if the officeholder fails to discharge the duties of the office for three consecutive months. The article contends that this law could require that Representative Giffords’ seat be declared vacant, although it also indicates that the Arizona Governor and other officials would be loath to take such a step.
On Tuesday, however, the print version of the Post explained that “As Gabrielle Giffords continues recovery, lawyers say Arizona statute won’t endanger seat.” This time the Post explains how “Washington lawyers” have debunked its original story (it doesn’t put it that way, of course). According to these lawyers, “any determination of a vacancy would have to be made by Congress.” Paul Bender is quoted as saying that “the state has no right to say when the office becomes vacant.”
So are these experts right? Up to a point. The original story was certainly mistaken to the extent that it implied Arizona had the authority to define what constitutes a vacancy in a congressional office. The issue of whether a vacancy has occurred is a constitutional question arising under the House Vacancies Clause (Article I, section 2, clause 4), which provides that “when vacancies happen in Representation from any State, the Executive Authority thereof shall issue Writs of Election to fill such Vacancies.” It is clear that neither the state nor the executive authority has carte blanche to define for themselves what constitutes a vacancy, and it is likely (though somewhat less clear) that they have no discretion in the matter. In other words, if a constitutional vacancy occurs, the Governor has the authority, indeed the duty, to call a special election, but the fact that the Governor (or the state) believes that a vacancy has occurred does not make it so.
So how does the Governor know if a vacancy has occurred? The vast majority of vacancies have been created by death, expulsion, or resignation, and there is seldom any doubt in these types of cases (although there are sometimes ambiguous resignations which require the exercise of judgment). In the rare instances which do not fall into one of these categories, Governors have not acted on their own, but only after the House has declared a vacancy. Nevertheless, there would appear to be no constitutional impediment to the Governor acting on her own initiative (nor, to my knowledge, has House precedent prohibited such action). Accordingly, the Arizona Governor could call a special election on the grounds that (in her opinion) Giffords’ seat has become vacant within the meaning of the House Vacancies Clause.
This decision could be challenged in state or federal court (just as the attempt to recall Senator Menendez was recently challenged in and invalidated by the New Jersey Supreme Court). It is possible that the court would not reach the merits of the case, however, on the grounds that it is the House which is the constitutional judge of the election and qualifications of its members. In the event that a special election were held, it would be up to the House to decide whether to seat the victor, which would necessarily entail a determination as to whether the seat was vacant in the first place.
On the merits, the answer is not so clear. The Constitution does not define what constitutes a vacancy. This makes it distinguishable from cases that are often cited regarding the qualifications of members, because the Constitution expressly identifies those qualifications. It might be argued that declaring a vacancy when a member is incapacitated is a backdoor way of establishing a new qualification for members, but this does not answer the real question– are there circumstances in which a member’s incapacity renders the office vacant?
In general, neither the House nor Senate have taken cognizance of lengthy incapacities of Members. As explained by Norm Ornstein in 2002 testimony before the House Judiciary Subcommittee on the Constitution, “[m]any members have stayed in their elected positions for months or longer while comatose or clearly unable to perform their normal duties.” In one case, however, the House declared a vacancy when a congresswoman-elect was in a coma and unable to take the oath of office. Conceivably this precedent could be extended to members who have been sworn in but become incapacitated to the point that they cannot perform any of the duties of the office. Doing so, however, would give rise to difficult line-drawing problems (how does one decide whether a member is permanently or merely temporarily incapacitated?).
In short, while the conventional wisdom holds that the Constitution does not permit a seat to be declared vacant because of the incapacitation of its occupant, it is more accurate to say that the matter is unsettled. That in turn gives rise, as Professor Sandy Levinson notes, to a significant uncertainty as to how the Congress would respond in the case of mass incapacitation.