Running mate: Before deciding who, McCain's question is how

DALLAS — Now that Sen. John McCain is headed to the nomination, he can begin thinking seriously about perhaps the most important decision he will have to make as the Republican presidential nominee: the selection of a running mate.

McCain and several senior campaign advisers insist that there is no short list of names, and no process to help him make his choice — merely a process to find a process. He directed his campaign to study past selection methods.

The choice of a running mate is always important, but it may be particularly so in McCain's case, given that, at 71, he is seeking to become the oldest candidate ever elected to a first term as president.

Michael Nelson, a professor of political science at Rhodes College who has written about the vice presidency, said there were basically three ways McCain could go: try to consolidate the Republican base by tapping a conservative; try to reinforce his appeal to independent voters by picking someone with crossover appeal; or try to win a swing state or region by taking geography into account.

Any of the three strategies, Nelson said, could be good as long as the selection seems presidential.

"I think that ever since the development of ICBMs [intercontinental ballistic missiles]," he said in a recent interview, "there's been a concern among voters that the vice president be someone who could step into the presidency literally at a moment's notice."

Several governors have been mentioned as potential running mates for McCain; their executive experience and ability to cast themselves as Washington outsiders are perceived as strengths. They include:

• Tim Pawlenty, of Minnesota, an early supporter;

• Charlie Crist, of Florida, whose last-minute endorsement helped McCain win that crucial swing state's primary;

• Jon Huntsman Jr., of Utah, an early supporter despite Mitt Romney's popularity in his state;

• Mark Sanford, of South Carolina, whose conservative reputation could help McCain with the base but who declined to endorse him this time.

Former governors have been mentioned as well, including Tom Ridge of Pennsylvania, whose support of abortion rights could cause McCain trouble with conservatives who are already wary of him. This category also includes his former primary opponents Romney and Mike Huckabee.

Huckabee, a former governor of Arkansas, has a reputation as a good campaigner but is distrusted by some economic conservatives for raising taxes in the past. Romney, a former Massachusetts governor with a business background, often sparred brutally with McCain, but endorsed him swiftly and would bring a financial background to the ticket.

Rob Portman, a former Ohio congressman and director of the Office of Management and Budget, could also bring a financial background.