WASHINGTON (AP)  American voters should know this week who will join Barack Obama as No. 2 on the Democratic presidential ballot, a critical decision for the first-term senator who is fighting off Republican John McCain's bid to paint off him as untested and unready for the White House.

Democrats open their national convention a week hence in Denver, and Obama's choice of a running mate remains the primary unanswered question as the party gears up for the final push to oust the Republicans from the executive mansion.

Top contenders for the vice presidential spot were Evan Bayh, a middle-of-the-road Indiana senator with an extensive Democratic pedigree; Virginia Gov. Tim Kaine, who leads a Republican-leaning state that Obama needs to put in his column in the Nov. 4 election, and long-serving Delaware Senator Joseph Biden, chairman of the Foreign Relations Committee who undertook a weekend trip to Russian-occupied Georgia.

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The crisis in Georgia, a U.S.-allied country that broke free from Russian domination after the Soviet empire collapsed in 1991, underlined Obama's need for a running mate with foreign policy gravitas to counter McCain's four terms in the Senate where he has served as Armed Services chairman and traveled extensively abroad.

Biden said he was invited to Georgia by its president, Mikhail Saakashvili, whose forces launched an attack to regain control of the breakaway South Ossetia region Aug. 7 but were overwhelmed and driven back by Russian troops, armor and attack air craft. Russia then took control of most of Georgia but said on Monday it was pulling its troops out under a European Union-negotiated agreement.

McCain has not yet named a running mate either. The Republican convention is Sept. 1-4.

Former Pennsylvania Gov. Tom Ridge, who supports abortion rights and whose name has been floated by McCain as a possible running mate, said he thought the Republican Party would accept a so-called pro-choice vice presidential candidate.

McCain riled some conservatives last week when he suggested his running mate could — like Ridge — support abortion rights.

"What he was saying to the rest of the world is that we need to accept both points of view," Ridge said on Fox television. "He's not judgmental about me or my belief. He just disagrees with me."

Ridge spoke on a weekend television talk show a day after McCain assured evangelical Christians during a forum on faith in California that he had a long record in opposition to abortion and would not change that stand. The abortion issue drew one of the starkest lines under policy differences raised Saturday night when both McCain and Obama were questioned separately by pastor Rick Warren in his Saddleback Church, a California megacongregation that claims 23,000 members.

As Obama was leaving the stage and McCain was taking his place, the two men shook hands and embraced briefly in the jam-packed church. But by Sunday, Obama had taken off the gloves and was again battering McCain as little different from unpopular President George W. Bush, a fellow Republican.

Obama also laid into McCain's campaign team for using "the same old folks that brought you George W. Bush" to paint Obama as unpatriotic and weak.

McCain spokesman Brian Rogers responded, "John McCain has never questioned Sen. Obama's patriotism, but he clearly does question Sen. Obama's experience and judgment."

Obama, who has been put on the defensive by a series of attacks on his character, experience and readiness for the presidency, has been responding to the McCain accusations blow for blow.

McCain has sought to make the 2008 presidential contest a referendum on Obama, while trying to duck his associations with Bush, who has become deeply unpopular with voters disenchanted with 5 1/2 years of war in Iraq and a badly stumbling economy.

McCain was in Florida, meanwhile, for a fundraising event which was canceled as Tropical Storm Fay moved toward the state. The Republican candidate was briefed on the storm.

On Monday, McCain was to address the Veterans of Foreign Wars convention in Orlando, which should provide a warm reception to the former fighter pilot who spent 5 1/2 years as a prisoner in North Vietnam. Obama was scheduled to speak on Tuesday, followed by Bush on Wednesday.

On Sunday night, Obama raked in $7.8 million at three separate fundraisers in San Francisco. Some individuals paid $28,500 to attend.

"John McCain, all he wants to do is talk about me," Obama told supporters. "They know they can't win on the issues. So what they'll do is they'll try to scare people: 'He's risky. He's risky. We're not sure."'

In April, at another fundraiser in this prosperous, liberal city in Northern California, Obama made his infamous remarks about bitter small town voters who "cling" to guns and religion. Rivals used those comments to brand him as elitist.

Obama avoided any such characterizations this time but did say many voters are angry and confused. "The fact of the matter is, at a certain point, when government has not been serving the people for this long, people get cynical," he said.

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