A Christian Science Monitor op-ed argues that this is advisable, and constitutional. I don't think so, because the Twenty-Second Amendment's bar on a President serving more than two terms also applies to the Vice-President (for reasons I touch on below). But, as I suggested here and here, the matter is more complex than it first appears.

Here are the relevant constitutional provisions, in relevant part:

• The Twelfth Amendment: "[N]o person constitutionally ineligible to the office of President shall be eligible to that of Vice-President of the United States."
• The Twenty-Second Amendment: "No person shall be elected to the office of the President more than twice ...."
• Article II, § 1, cl. 4: "No person except a natural born citizen, or a citizen of the United States, at the time of the adoption of this Constitution, shall be eligible to the office of President; neither shall any person be eligible to that office who shall not have attained to the age of thirty five years, and been fourteen Years a resident within the United States."

The question, then, is this: Does "constitutionally ineligible to the office of President" mean "constitutionally barred from being elected to the office of President," or "constitutionally barred from serving in the office of President"?

If it means the former — if "eligible" is roughly synonymous, for elected offices, with "electable" — then Bill Clinton would be ineligible to the office of President because of the Twenty-Second Amendment, and thus ineligible to the office of Vice-President because of the Twelfth Amendment. On the other hand, if "eligible" means simply "constitutionally barred from serving," then the Twenty-Second Amendment doesn't speak to whether Bill Clinton is eligible for the office of President, since it only says that he may not be elected to that office. And because there's nothing in the constitution that makes Clinton ineligible for the Presidency, the Twelfth Amendment doesn't make him ineligible for the Vice-Presidency.

My tentative answer is that "eligible" roughly means "elected." I realize that this is far from perfect evidence — it's 40 years later than the usage — but the earliest law dictionary the library could find for me, Bouvier's (1843), defines "eligibility" as "capacity to be elected." (I take it that, by extension, for appointed offices it would mean "capacity to be appointed.") If that's how the term was understood in 1804, then Clinton would not be eligible to the office of President, and thus under the 12th Amendment not eligible to the office of Vice-President.

Some mid- to late 1800s cases also define eligible as referring to "capacity of holding, as well as capacity of being elected to an office" (see Carson v. McPhetridge, 15 Ind. 331 (1860)); but that's in the context of saying that someone who isn't eligible to an office isn't capable either of holding the office or being elected to it. I've seen no evidence that, contrary to the Bouvier's definition, a person would have been seen in the early 1800s as being "eligible" to an office when he was legally barred from being elected or appointed to it, and the only question related to whether he could automatically assume it under some succession statute.

On the other hand, Bruce G. Peabody & Scott E. Gant, The Twice and Future President, 83 Minn. L. Rev. 565 (1999), argues the contrary, though I find myself tentatively unpersuaded by the article's position:

First, it is by no means clear that the term "eligibility" as used in the Twelfth Amendment refers to or incorporates a person's reeligibility under the Twenty-Second Amendment. At the time the Twelfth Amendment was written there was, of course, no Twenty-Second Amendment; therefore, the Twelfth Amendment could not have originally meant to preclude someone from being Vice President who had been elected President twice. Rather, the Twelfth Amendment's reference to "eligibility" likely pointed only to the "eligibility" provision of Article II, Section 1, clause 4 ....

Second, even if the Twelfth Amendment's eligibility provision is to be read in light of the proscriptions of the Twenty-Second Amendment, it could be read as affecting only persons who would become President. If this understanding is correct, the Twelfth Amendment's provision that "[n]o person constitutionally ineligible to the office of President shall be eligible to that of Vice President of the United States" has no effect on individuals who might simply act as President. In other words, a Vice President "constitutionally ineligible to the office of President" might occupy the vice presidency and eventually act as President, while being ineligible to assume that Office by becoming President through succession....

Third, and most importantly, even under the most expansive reading of what constitutional "eligibility" might include[,] ... we do not believe [for reasons elaborated elsewhere in the article -EV] an already twice-elected President is "constitutionally ineligible to the office of President." ... Even if one leaves aside [scenarios involving succession from the Vice Presidency to the President], there are other non-electoral means of reassuming Office available to a twice-elected President [-- a person's acting as President under succession statutes triggered by the unavailability of either the Vice-President or Presesident, or becoming President if chosen by the House of Representatives when no candidate gets a majority of the electoral votes]. Thus, if the meaning of "eligibility" under the Twelfth Amendment was transformed with the adoption of the Twenty-Second Amendment, the Twenty-Second Amendment still does not render twice-elected Presidents "constitutionally ineligible to the office of President," and it therefore cannot be said that the Twelfth Amendment prohibits a twice-elected President from serving as Vice President.

The issue, incidentally, had come up in 1964, when there was talk of a Goldwater-Eisenhower ticket (thanks to reader David Tenner for the pointer).