WASHINGTON Few events in U.S. presidential races spark a media frenzy like the choice of a running mate.
Now that Democrat Barack Obama and Republican John McCain have secured their parties' nominations for the White House, the guessing game has begun in earnest.
Will McCain, who is 71, pick a youthful candidate but one also seen as fully ready to step in should health problems arise for him?
Is Obama, a 46-year-old first-term U.S. senator, looking for vice presidential possibilities with solid foreign policy credentials to lend extra heft?
Or will he tap his former rival, Sen. Hillary Clinton, for what her supporters believe would be a "dream ticket" of the first black to win a major-party presidential nomination and a former first lady who sought to become the first woman to win the White House?
The search process is already well under way for McCain, who became the presumptive Republican nominee in early March.
Last month, the Arizona senator stirred speculation he was narrowing his short list when he held a barbecue at his Sedona, Arizona, vacation home and invited three likely vice presidential contenders: former Massachusetts Gov. Mitt Romney, Louisiana Gov. Bobby Jindal and Florida Gov. Charlie Crist.
Obama has named a committee to lead his search. Its members are Caroline Kennedy, daughter of the late President John F. Kennedy, former Deputy Attorney General Eric Holder and Jim Johnson, former head of mortgage giant Fannie Mae.
As Obama took his victory lap last week, the debate over whether he should choose Clinton dominated the headlines after she told supporters she was open to the idea.
Many analysts believe an Obama-Clinton ticket is unlikely, in part because of questions about whether the two have enough of a rapport. Clinton would also bring memories of the scandal-plagued years of her husband Bill Clinton's presidency, which might undercut Obama's message of change.
"Politics can turn on a dime, so anything is possible but I'd be shocked if he selected Hillary Clinton," said political scientist Larry Sabato of the University of Virginia.
Plenty of other names are circulating.
Among them are former Senate Majority Leader Tom Daschle of South Dakota, a close adviser to Obama; Virginia Sen. Jim Webb, a decorated Marine veteran of the Vietnam War; New Mexico Gov. Bill Richardson, a Hispanic and former ambassador to the United Nations; Indiana Sen. Evan Bayh and Kansas Gov. Kathleen Sebelius.
Obama emphasized he was in no rush. "I am a strong believer in doing this in a careful deliberate way outside of the day-to-day political pressures that inevitably start up during this kind of thing," he said.
For all the attention paid to the selection of a running mate, some see the job as overrated. Vice presidents attend many funerals, give advice behind the scenes and most important, serve as an understudy to the president.
John Nance Garner, who served for eight years as No. 2 to President Franklin Roosevelt, was famously quoted as saying the job was not worth a "bucket of warm spit" because a vice president was expected to fall into line with the person occupying the Oval Office and lacked a separate power base.
That view of the job has changed. Vice President Dick Cheney, a key player in the decision to invade Iraq, is viewed by many scholars as the most powerful No. 2 in U.S. history.
But the unpopular Cheney is probably not a role model for the selection process this year.
"The example of Dick Cheney guarantees both candidates will insist their vice president won't be as powerful," Sabato said. "If the nominees are compared to Dick Cheney, they are in trouble."
Running mates are often chosen because they hail from states seen as crucial in a general election. That was important for Democrat John F. Kennedy when he chose Lyndon Johnson of Texas in 1960.
Some running mates are chosen to unify a party after a divisive primary battle. That was the case when Republican Ronald Reagan picked George H.W. Bush in 1980.
No matter what drives the choice, the fanfare is justified because it is a moment for candidates to demonstrate their decision-making skills.
A poor choice can reflect badly on a candidate's judgment. Democrat George McGovern learned that the hard way in 1972 when he had to replace his first choice for vice president, Thomas Eagleton, when it was revealed Eagleton had mental health problems.
"This is probably the most important decision that a presidential candidate will make between securing the nomination and Election Day in November," said William Galston, a former adviser to President Bill Clinton and now a scholar at the Brookings Institution.
(Editing by Eric Walsh)