A final nail has been driven into the coffin of one of the most venerable calculations in American politics by the selection of Delaware Sen. Joe Biden and Alaska Gov. Sarah Palin as running mates of Barack Obama and John McCain. The equation is that a crucial asset of running mates is that they can carry their home states and thus contribute to assembling the 270 electoral votes needed to claim the presidency. Delaware and Alaska offer a total of six electoral votes.

If this standard for the selection of the No. 2 person on the ticket enjoyed any validity, then Biden and Palin would have been well down the list.

It is now clear that other factors have trumped the favorite son (or daughter) as a criterion in the choice of a running mate, because it is an advantage that either cannot be proved or is just plain wrong. The belief that voters in a state will support a presidential candidate because one of their own is his running mate is an echo from a period in which local loyalties were much stronger than national ties.

Yet the belief persisted among political professionals and commentators that voters would deliver their state's votes on the basis of local pride, even though recent history and studies in the 1980s indicated that few voters were influenced by state loyalty. But these experts invariably pointed to the one election in the last half a century in which a running mate did carry a state that the ticket would otherwise have lost: vice presidential candidate Lyndon Johnson's Texas in 1960.

Johnson's 44-state sweep in 1964 would certainly have included Minnesota even if Hubert Humphrey, a Minnesotan, had not been on the ticket. Richard Nixon put Maryland Gov. Spiro Agnew on the ticket and lost Maryland.

Likewise, Walter Mondale's choice of New York congresswoman Geraldine Ferraro in 1984 did not win him that traditionally Democratic state.

But his selection of her did mark a major change in the criteria for selecting a running mate: the hope of carrying a demographic group — in this case women — rather than a geographic unit.

Other factors, such as reconciling tensions between wings of the party, figured in decisions such as Jimmy Carter's choice of Mondale in 1976 as a gesture of reassurance to liberals or Ronald Reagan's choice of George H.W. Bush in 1980 as a sop to moderates.

But throughout the campaign, we have continually heard arguments being made for potential running mates based on the electoral votes their home states would surely provide. Such talk certainly kept Indiana Sen. Evan Bayh in the running until the Obama campaign concluded that the inclusion of the popular senator and ex-governor would probably not have been enough to overcome Hoosier resistance to Obama, who fared so poorly there against Hillary Clinton in this year's primary.

And because Biden was born in Scranton, Pa., some commentators insist on seeing a "favorite son" advantage for the Democrats in that important swing state. If Biden does help bring in votes there, it is much more likely to be because of his demographic appeal — to white, working-class Catholics — rather than geographic loyalty.

As McCain's reasons to choose Palin become clearer, it is safe to say the hope of winning over Clinton supporters was subordinate to Palin's ability to reassure GOP social conservatives. For Obama, the choice of Biden was an offset to his own limited experience in foreign policy and national security.

Obama and McCain understood that Americans are not attached to their localities as they once were, that we are a nation of media markets, and that partisanship prompts voters to ignore origins for ideology.

Ross K. Baker is a professor of political science at Rutgers University. He wrote this commentary for the Los Angeles Times.