While Obama sought to dismiss a new ABC News-Washington Post survey, his campaign must be concerned by its findings that white women have moved from backing Obama by 8 points to supporting McCain by 12 points. Overall, the poll showed Obama still ahead of McCain by a statistically insignificant one percentage point, 47 to 46.
Obama said he was not particularly concerned: "I just think that the notion that people are swinging back and forth in the span of a few weeks or a few days, this generally isn't borne out."
The big shift in McCain's support among the key voting bloc surfaced after he named Alaska Gov. Sarah Palin as running mate on the Republican ticket. His support has climbed steadily in the polls since the party ended its national convention on Thursday.
The daily Gallup Poll tracking survey showed McCain jumping to a 5-point margin, 49 to 44, signaling a major shift in voter sentiment, at least for the time.
In Ohio Tuesday, Obama derided President George W. Bush's decision to keep Iraq war troop levels largely unchanged, linking McCain to the unpopular president's war policies - a recurring theme for the first-term Illinois senator.
The 47-year-old Democrat has campaigned on a pledge to withdraw U.S. troops from Iraq within 16 months of becoming president. Bush's announcement on Tuesday allowed Obama, however briefly, to refocus attention from Palin - who has excited many conservative and women voters who were lukewarm about McCain.
But U.S. voters have shown themselves weary of the two wars being fought by American troops and more deeply anxious about the shaky American economy.
Earlier in the day, Obama attacked McCain over his record on improving education, as he looked to pick up support of independent voters in Ohio, a crucial swing state.
Obama's targeting of education - a subject on which Republicans have typically focused - reflects his efforts to recapture some of the momentum in a White House race.
The Democrat vowed to double federal funding for charter schools, publicly funded but independently run schools that are held accountable for their results. Obama accused McCain of having done nothing in his long Senate tenure to improve education and said the country needs a bipartisan drive to stop the deterioration of the its educational system.
Obama, meanwhile, appears to have been surprised by Palin's nomination and has been on the defensive as she and McCain have tried to steal away with their rival's central campaign promise - change in Washington.
Palin was a virtual unknown on the national political stage until she was announced as McCain's running mate. Since then a small industry has sprung up to investigate her background. The McCain campaign announced on Tuesday it was setting up what it called "a truth-squadding operation designed to push what they deem as 'smears' about Gov. Sarah Palin out of circulation."
The 55-person panel, primarily current and former Republican women officeholders, was established "to combat false info in the press, and the campaign will send 'truth squad alerts' as warranted," said campaign spokesman Brian Rogers.
Since she was chosen to fill out the McCain ticket, Palin quickly reported that her unmarried teen daughter was pregnant and has been dogged by unfavorable publicity about her time as mayor of a small Alaska town and as governor of the state.
Bush on Tuesday played into what Obama had hoped would be one of his strengths when the president said he would keep the U.S. force strength in Iraq largely intact until the next president takes over and outlined what he called a "quiet surge" of additional American forces in Afghanistan.
Obama fired back that the announcement means taxpayers "will continue to spend $10 billion a month in Iraq while the Iraqi government sits on a $79 billion surplus."
"In the absence of a timetable to remove our combat brigades, we will continue to give Iraq's leaders a blank check instead of pressing them to reconcile their differences," Obama said while campaigning in Ohio, a crucial swing state.
"Now, the choice for the American people could not be clearer. John McCain has been talking a lot about change, but he's running for four more years of the same foreign policy that we've had under George Bush," Obama said.
Bush's announcement means that the U.S. will withdraw about 8,000 combat and support troops by February - a drawdown not as deep or swift as long anticipated - and what likely will be Bush's last major move on troop strategy in Iraq.
Bush also spoke of raising the troop level in Afghanistan to nearly 31,000, compared with about 146,000 in Iraq. He said that a Marine battalion that had been scheduled to go to Iraq in November would go to Afghanistan instead, and that that would be followed by one Army combat brigade.
But the limited focus on Afghanistan, the one-time safe-haven for al-Qaida mastermind Osama bin Laden, and where Taliban militants are regaining strength, left the Republican president open to criticism that his focus in the so-called "war on terror" continues to be misplaced.
McCain said in a statement that Bush's announcement "demonstrates what success in our efforts there can look like," and argued that it "stands in clear contrast to the reckless approach long advocated by Sen. Obama."
McCain also backed additional forces in Afghanistan, and said, "Sen. Obama believes we must lose in Iraq to win in Afghanistan."
Obama has proposed sending about 7,000 additional troops to Afghanistan to combat the Taliban and chase down bin Laden, who is believed to be hiding along the rugged border in neighboring Pakistan.
McCain has called for a smaller number of troops in Afghanistan. He says U.S. forces should not be withdrawn from Iraq until conditions on the ground dictate a departure. The particulars of those conditions, however, have not been defined.
