VP news expected as early as today

Barack Obama gave his clearest signal yet that he has settled on a running mate when he announced Tuesday he would appear Saturday in Springfield, Ill, where he launched his campaign. Meanwhile, John McCain is expected to announce his choice in Ohio on Aug. 29 -- his 72nd birthday and just days before the GOP convention in St. Paul. ¶ For all the talk, running mates seldom are a factor in November outcomes. But it is the most important decision each candidate makes before gaining his party's nomination, and it could reveal much about his judgment. Here is a look at the strengths and liabilities of the prospective choices:

THE DEMOCRATS

JOSEPH BIDEN

How he helps: Biden, as chairman of the Senate Foreign Relations Committee, would bring a wealth of foreign policy experience, something Obama lacks. Just this past weekend he was in Georgia at the request of President Mikhail Saakashvili. Biden, 65, of Delaware, has been in the Senate since 1972, 10 years before McCain was first elected.

How he doesn't: The fact that Obama would turn to Biden in an effort to offset his own foreign-policy inexperience could be seen as a lack of confidence. Also, Biden has a spotty political history. He fared poorly as a presidential contender this year and is still dogged by his decision to drop out of the 1988 campaign after he was caught lifting lines from a speech by a British politician. Earlier this year, he apologized for describing Obama as "articulate" and "clean."

Geographically, Biden would bring little. Delaware has voted Democratic in recent contests and has just three electoral votes.

EVAN BAYH

How he helps: Bayh, 52, a popular two-term former governor of Indiana and son of former Sen. Birch Bayh, could help put red-state Indiana and its 11 electoral votes in play. Indiana has not voted for a Democrat for president since 1964, but Democrats view it as competitive this year. Bayh has a centrist record and executive experience as governor. He also supported Hillary Rodham Clinton in the primaries, and that could help Obama with her supporters.

How he doesn't: Location. Having two senators from neighboring Midwestern states wouldn't amount to much geographic diversity. Also, Bayh's early support for the Iraq war could be a liability.

KATHLEEN SEBELIUS

How she helps: Sebelius, 60, as governor of traditionally Republican Kansas, would bring executive experience to the ticket and could help reach out to moderate Republicans and to those intent on seeing a woman on the ticket.

How she doesn't: She is the least well-known contender. And her presence on the ticket still might not be enough to win over her solidly red state and its six electoral votes. Also, die-hard Clinton supporters might react negatively to a woman on the ticket other than Clinton.

TIM KAINE

His strengths: Kaine, 50, is a charismatic speaker and popular Democratic governor in traditionally Republican Virginia. That could help reinforce Obama's outside-Washington theme and help to put a GOP state in play. Kaine might also appeal to fellow Catholics.

His weaknesses: Kaine is a lot like Obama in terms of age and relative lack of experience. Some pundits, however, view the fact that Obama has already given a convention speaking role to Virginia's former Gov. Mark Warner -- also mentioned as a possible VP contender -- as an indication that Kaine may not get the nod since it seems unlikely two prime speaking spots would go to Virginians.

THE REPUBLICANS

TIM PAWLENTY

How he helps: Minnesota's governor could bring McCain the support of conservative Republicans and help in a state that has supported Democratic presidential candidates since 1976. Minnesota has 10 electoral votes.

At 47, he is Obama's age. Growing up in St. Paul, site of the GOP convention, he has a blue-collar background and a reputation as a budget cutter and tax-cut advocate. His veto of a string of bills has made him unpopular with Minnesota's Democratic-dominated Legislature.

How he doesn't: While generally seen as a safe choice, Pawlenty is little known outside his home state. He also comes across to some as bland.

MITT ROMNEY

How he helps: Romney, 61, who was McCain's closest competitor in the GOP primaries, would bring to the ticket economic and executive experience that McCain doesn't have. The former Massachusetts governor was CEO of the 2002 Salt Lake Winter Olympics. As head of Bain Capital, he helped launch the Staples office supply chain and buy Domino's Pizza.

Romney is popular in Utah and Colorado, states with large numbers of residents who, like Romney, are Mormons. And he grew up in Michigan, where his father was governor and a GOP presidential contender.

How he doesn't: Questions remain about Romney's shifting stance on such issues as abortion and gay rights as he abandoned once-moderate politics to court social conservatives.

TOM RIDGE

How he helps: Ridge, 62, is a popular former Pennsylvania governor and, like McCain, a Vietnam War veteran. After 9/11, President Bush named him as director of the Office of Homeland Security, and later secretary of the new Department of Homeland Security.

How he doesn't: Ridge's biggest liability could be his support for abortion rights. McCain's recent comments that he might consider someone with such views generated a torrent of criticism from social conservatives. Still, GOP officials say top McCain advisers have been reaching out to gauge the impact of putting an abortion-rights supporter on the ticket, underscoring how seriously McCain might be considering Ridge or Sen. Joe Lieberman. Such a choice could raise the prospect of acrimony at the convention.

JOE LIEBERMAN

How he helps: Picking Lieberman, 66, one of McCain's most outspoken campaign-trail partners, would signal a reach across the political aisle. Lieberman was Democrat Al Gore's running mate in 2000 and now represents Connecticut in the Senate as an independent.

How he doesn't: While the choice might be applauded by some as a bold bipartisan move, it could also trigger a backlash among some Republicans and Democrats. House Speaker Nancy Pelosi, D-Calif., for instance, recently accused Lieberman of "totally irresponsible" remarks about Obama.

ASSOCIATED PRESS