What makes for a "good" vice presidential candidate? History suggests no single pattern. Typically, a presidential nominee, in consultation with party chieftains, looks to someone who can bridge warring political factions, balance the ticket geographically or secure a coveted battleground state.
In 1960 John F. Kennedy chose Senate majority leader Lyndon Johnson so that the powerful LBJ could run interference with hostile Southern Democrats -- and help JFK capture Texas. Johnson complied -- in part, by organizing an electoral fraud -- which helped put Kennedy over the top in one of the closest elections in U.S. history.
But the pairing almost didn't happen. JFK deeply distrusted LBJ, and his brother Bobby despised him. Kennedy ended up extending the VP offer through an emissary, and was reportedly shocked when Johnson, who resented the entire Kennedy clan, accepted. Bobby even tried to get LBJ to step down, but the proud Texan refused.
Much the same was true in 1980, when Ronald Reagan surprised Republicans by picking George H.W. Bush as his running mate. Reagan was the party's Spartacus, and his merry band of insurgents viewed Bush as a shill for the GOP establishment. But the unlikely pairing -- Bush had earlier lampooned Reagan and his "voodoo economics" en route to victory in Iowa -- gave different party factions a common stake in the ticket, and the two men buried the hatchet to win.
Of course, seeking party unity doesn't always mean choosing your runner-up. If it did, Barack Obama might well have picked Hillary Clinton as his running mate in 2008. Instead, Obama chose a party graybeard, Delaware Sen. Joe Biden, for a completely different reason: to offset the impression that he was too "inexperienced" to be president, and to defuse racial concerns among white voters.
Obama's opponent, John McCain, likewise passed over his party's runner-up -- Mitt Romney -- but it was for the opposite reason: to balance his own reputation for experience -- and moderation -- with a passionate firebrand representing the Christian right. But the choice of former Alaska governor Sarah Palin turned out to be a huge blunder. When the full scope of her lack of readiness for high office became known, voters began questioning not only McCain's experience, but his judgment, too.
The Biden versus Palin episode highlights another evolving trend in the "Veep-stakes": the need for Number Twos to be fully credible as prospective replacements. With the assassination of JFK, the resignation of Richard Nixon, the near-assassination of Ronald Reagan and the impeachment of Bill Clinton, the question of presidential "succession" looms larger than ever. And as a result, voters and the national media are scrutinizing VP qualifications like never before.
There's also the fact the institutional role of the vice presidency has grown enormously in recent years. It's no longer a job that "isn't worth a warm bucket of spit," as John Nance Garner once famously described it. While the U.S. Constitution still limits the VP's role to presiding over the U.S. Senate -- and only casting a vote in the event of a tie -- presidents have begun assigning their seconds-in-command far weightier responsibilities.
Ronald Reagan's VP, George H.W. Bush, a former CIA director, helped fashion his boss' foreign and defense policy, which included his still-secret role in the Iran-contra affair and other questionable activities against Nicaragua that may have violated international law. And under Bush's son, Dubya, the bureaucratic power and influence of vice president Dick Cheney grew to gargantuan proportions. Many have described Cheney as Bush's "co-president."
But it's not just Republicans. Biden has also played a formative role in shaping U.S. foreign and defense policy, expanding the far more limited role that Al Gore played for Bill Clinton. In Afghanistan, Biden's steadfast defense of "counter-terrorism" not "counter-insurgency" -- and his vocal rejection of "nation-building" -- kept the generals from dragging the country -- and Obama -- into a more prolonged and messy war.
And Biden has also proven his mettle on the Hill, helping to defuse criticism of key Obama policies, while reassuring -- or gently arm-twisting -- wavering senior Democrats. Biden is now slated to play a highly visible and influential role in shaping Obama's re-election campaign.
Why is the power of the vice-presidency growing? It could be that the demands of the "imperial" presidency have simply become too burdensome a responsibility for one man (or woman). And, of course, having a VP quietly take on tasks away from the glare of the national spotlight can also be useful politically. It helps deflect partisan criticism aimed at the White House, or, in the case of Reagan and Bush and Dubya and Cheney, helps shield the president himself from moral and legal blame.
It could also be that a fiercely budget-conscious American public now expects its VPs to earn their taxpayer-funded salary by performing more than strictly "ceremonial" duties. In either case, the traditional notion that the "bottom half of the ticket" has little influence over presidential elections no longer seems to hold.
Which brings us to 2012, and whether the GOP has learned from the Palin disaster. Apparently not, since so much of the discussion among Republican still centers on finding a running mate who can pass muster with the insurgent Tea Party -- a Marco Rubio, for example, or even New Mexico governor Susana Martinez, both of whom have the added advantage of being Hispanic.
The problem? They're both extremely young, with less governing experience than even Palin had. Rubio is already under fire for embellishing his personal biography -- it turns out his family didn't really flee from Castro -- and there are other skeletons in his closet dating to his days as Florida's speaker of the house.
Alternatively, the GOP could go in the opposite direction: choose a Biden-like elder statesman like former New York City mayor Rudy Giuliani -- still a hero, especially in conservative circles -- or even the insufferable -- for some, at least -- Newt Gingrich. Either man could prove a convenient foil to a candidate like Romney, who's touting his experience in business and the private sector while casting himself as a Washington "outsider."
In the end, Republicans are likely to find themselves in the same dilemma with their running mate selection that they currently face with their prospective nominee: whether passion and ideological "consistency" should trump "electability." In 2008, they tried to bridge the gap with McCain and Palin but the "balancing" act backfired. Now, given the public's increasingly high expectations for vice presidents -- and facing a still-popular incumbent -- the party can't afford to make the same mistake if it wants a real shot at winning.