Guessing game begins on Obama and McCain VP picks

By Caren Bohan - Analysis

WASHINGTON (Reuters) - 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.