joe_biden.jpegDENVER (AP) _ Democrat Barack Obama got what he may need most when he chose Sen. Joe Biden of Delaware as his running mate _ a vice presidential candidate with encyclopedic foreign policy know-how and a political brawler ready to take on Republican John McCain's frontal assault on his opponent's newness on the national stage.

Through the month of August _ in the days leading up to the national party conventions _ McCain whittled away at Obama's slight lead in the polls with relentless attacks designed to paint the first-term Illinois senator as an inexperienced, celebrity-seeking elitist not ready for the White House.

While the 47-year-old Obama fought back blow-for-blow and even adopted some negative tactics himself, his campaign has not adopted the kind of visceral sharpness he is facing from McCain's operation.

It will be hard to imagine Biden, who is 65, being as low-key as was Obama after McCain charged his opponent this summer with being ready to lose the Iraq war for the sake of winning the presidential election. Obama has sought, as he can, to moderate his responses _ some say to avoid looking like an angry black man in an election contest that could put the first African American in the U.S. presidency.

Biden, a working-class Irish Catholic with 35 years in the legislative cauldron of the U.S. Senate, shows none of Obama's reticence to go for the jugular.

Fresh from introducing Biden, Obama set his sights on the battleground states of Wisconsin, Iowa, Missouri and Montana before he accepts the nomination on Thursday at a football stadium in Denver. The Democratic National Convention begins on Monday with speakers including Obama's wife, Michelle, and a video tribute to liberal icon Sen. Edward M. Kennedy, who is battling a malignant brain tumor.

Biden returned to Delaware after the ticket's first joint appearance Saturday in Springfield, Illinois, where Obama had begun his campaign in February 2007. Biden attended church near his home in Greenville, Delaware. He left the service without commenting to reporters.

Obama on Sunday was attending church before a campaign event in Eau Claire, Wisconsin, a city of 65,000 about 85 miles east of St. Paul, Minnesota, site of the Republican convention that begins Sept. 1. He was expected to discuss ways to stimulate the economy and help middle-class families.

Democrats quickly coalesced around Obama's selection of Biden. House Speaker Nancy Pelosi said Sunday that Biden offered “the full package.'' She said he “has challenged the status quo. And he's even criticized Senator Obama, so it's a tribute to Senator Obama that he's not just choosing a yes man but a person who will speak what he believes.''

In introducing Biden as his running mate, Obama called him a man who is “ready to step in and be president.'' And, in a clear shot at McCain, added that the Delaware senator is “what many others pretend to be _ a statesman with sound judgment who doesn't have to hide behind bluster to keep America strong.''

Biden then took the microphone and showed his stuff, recalling McCain's recent inability to say how many homes he owns even as Americans are struggling not to lose theirs to mortgage bankers.

“Ladies and gentlemen, your kitchen table is like mine. You sit there at night … after you put the kids to bed and you talk, you talk about what you need. You talk about how much you are worried about being able to pay the bills. Well, ladies and gentlemen, that's not a worry John McCain has to worry about. … He'll have to figure out which of the seven kitchen tables to sit at,'' Biden said.

Even though most polls predict Democrats making notable gains this year in Congress _ given the unpopularity of President George W. Bush and Republican scandals _ Obama has been unable, so far, to open a significant lead as the Democratic National Convention opens here Monday.

While he displayed phenomenal political skills, rocketing from the Illinois state legislature to his party's presidential nomination in four years, Democratic insiders believe that many Americans still feel they do not really know him.

Biden was clearly chosen over lesser-known Democrats to plug holes in Obama's relatively thin resume on the national political scene and to blunt McCain's relentless attacks on his lack of experience at a time when the United States is fighting two wars. McCain has also benefited from concerns raised by Russia's recent invasion of Georgia.

While polls show voters are most concerned about the country's wobbly economy _ home mortgage foreclosures, high fuel and food costs and growing unemployment _ McCain's appeal appears to be growing out of the lingering shock to Americans' sense of security from the Sept. 11, 2001, terror attacks.

McCain called Biden a “wise selection,'' but said he believed there was still plenty to criticize.

“I know that Joe will campaign well for Senator Obama, and so I think he's going to be very formidable,'' McCain told CBS News. “I've always respected Joe Biden, but I disagreed with him from the time he voted against the first Gulf War to his position where he said you had to break Iraq up into three different countries. We really have different approaches to many national security issues.''

McCain's campaign has already come out with two ads trying to cast doubts about the Democratic candidate's choice of a running mate.

The latest ad, released by the campaign early Sunday, tries to sow discord within Democratic ranks by questioning the motives of Obama in passing over his former chief rival, Sen. Hillary Rodham Clinton, and settling on someone who fared far worse in the primaries.

It features clips of Clinton during the primary battle saying critical things about Obama, including, “Sen. Obama's campaign has become increasingly negative.''

A voiceover announcer says, “She won millions of votes but isn't on the ticket. Why? For speaking the truth.''

Biden dropped out of the Democratic presidential race after a poor showing in the Iowa caucuses, the first contest.

Chief Obama strategist David Axelrod said in an interview on ABC television's “This Week'' Sunday that Obama “has a high regard for Senator Clinton. She's going to be an important voice in this campaign, she's going to be an important voice in moving this country forward in the next administration. But he felt Senator Biden would be the best fit for him at this time.''

In a gesture to Clinton, the party's credentials committee was poised Sunday to restore full voting rights at the convention to delegates from Florida and Michigan, initially stripped of all their delegates for holding too early primaries. With his nomination not in doubt, Obama sought the show of unity in hopes of shoring up support in those two important states that were won by Clinton in the primary campaign.

In addition to Biden's long resume, including his chairmanship of the Senate Foreign Relations Committee, “he's an independent guy who will tell the president what he needs to know even if he doesn't want to hear it,'' Axelrod said.

While Biden, a 35-year Senate veteran, provides a boost to the ticket's resume in foreign affairs, Obama also expects his running mate to help him appeal to middle- and working-class voters in battleground states like Ohio and Pennsylvania who favored Clinton, who nearly upended Obama in the primaries.

“For decades, he has brought change to Washington, but Washington hasn't changed him,'' Obama said, attempting to blunt an emerging Republican line of attack that notes Biden's long tenure in the Senate.

“He's an expert on foreign policy whose heart and values are rooted firmly in the middle class.''

Biden picked up on Obama's pledge to bring change to the nation, criticizing McCain as offering a continuation of Bush's unpopular policies.

“You can't change America when you know your first four years as president will look exactly like the last eight years of George Bush's presidency,'' Biden said.

McCain, who is expected to announce his running mate on Friday, holds a 2-1 lead over Obama as more knowledgeable on world affairs and as better suited to be commander in chief, according to an ABC News-Washington Post poll released early Sunday. The same poll, which gave Obama a slight 49 percent to 43 percent lead, found that three-fourths said the addition of Joe Biden as Obama's running mate would make no difference in their vote, while the remainder were evenly split on whether it would make them more or less likely to vote for Obama.

Several Republican officials, meanwhile, said that McCain had not settled on a running mate, although former Massachusetts Gov. Mitt Romney and Minnesota Gov. Tim Pawlenty were under serious consideration.

Pictured above is Sen. Joe Biden.