This is Part III of the ongoing list of McCain's prospective vice presidential running mates.

Mike Rounds

Pros: Young and telegenic conservative governor from the Mid-West.

Cons: South Dakota obviously is not in play. Catholic religion would be a major problem for certain elements of the Protestant right. Given that John Thune is available -- with Thune also fitting the profile of a young and telegenic conservative -- it's not necessarily clear Rounds would be the best Veep selection even from his home state.

Jim Gilmore

Pros: Former governor of a state likely to be very competitive and which possesses a material number of Electoral College votes. Sufficiently conservative. Would add geographic balance to the ticket.

Cons: Has not won an election since 1997. Slightly older than ideal.

Judd Gregg

Pros: Would all but guarantee New Hampshire flipping back into the GOP column. Has executive experience (state governor) to go along with experience overseeing various key U.S. Senate committees. Would add geographic balance to the ticket.

Cons: Would open up a U.S. Senate seat the party ill can afford to lose. A bit older than ideal. Not conservative enough for various elements.

Chris Cox

Pros: Strong conservative with some executive experience (SEC Chair) and a solid legislative record over many terms in the U.S. House. Relatively young.

Cons: Never has won a statewide election. If Obama winds up as the Dem nominee, then McCain's chances of winning Cox's home state of California mostly are derived from cultural and racial issues, i.e., Latinos and especially Asians will vote against Obama in droves, and Cox's presence on the ticket won't really affect the outcome in that state.

John Ensign

Pros: Young conservative (lifetime ACU rating: 94). Hails from a potential battleground and has won two statewide elections there within the past eight years.

Cons: No drawbacks of real substance. Zero national name recognition, but as Quayle and Agnew proved that's not really much of an issue for the Veep choice.

John Thune

Pros: Telegenic and young conservative from the Mid-West.

Cons: South Dakota is not remotely in play. As alluded to above, given that Rounds is a governor, whereas Thune is a sitting U.S. Senator, it's not altogether clear Thune would be the best Veep selection even from his own state.

Rick Perry

Pros: Telegenic and relatively young conservative governor.

Cons: Texas obviously is not in play.

John Cornyn

Pros: Strong conservative. Relatively young.

Cons: Texas is not in play.

Haley Barbour

Pros: Strong conservative. Theoretically could boost McCain's appeal with evangelicals.

Cons: Mississippi is not in play. A bit older than ideal.

Jon Huntsman

Pros: Young and telegenic conservative governor.

Cons: Utah is not in play. Mormon religion would be a major problem for certain segments of the Protestant right.