McCain mocked what he called Obama's varying positions on the so-called "surge" that sent an additional 30,000 troops to Iraq last year but that was unpopular with the American public. Obama opposed the strategy at the time and has suggested that he would pull U.S. combat troops out of Iraq within 16 months of taking office.
McCain has increasingly tried to portray the Illinois senator as an ambitious but empty celebrity, a man with a way with words but not the expertise or experience to back his rhetoric. The 71-year-old military veteran's Saturday comments echoed an earlier statement that raised eyebrows when he appeared to question Obama's patriotism, charging that he "would rather lose a war in order to win a political campaign."
In his speech to the Disabled American Veterans convention Saturday, McCain said Obama had not only predicted the troop increase would not succeed but had taken steps to ensure its failure, saying Obama had tried to prevent needed funding for it.
"Not content to merely predict failure in Iraq, my opponent tried to legislate failure," McCain said.
Obama voted against one major military appropriations bill in May 2007, but otherwise has voted consistently for funding to support the war, even though he opposed the initial invasion.
The surge has been credited with helping stabilize Iraq and reduce violence there. Obama has argued that it has not brought about the political reconciliation between rival Sunni and Shia factions needed to create lasting peace in the country.
Obama has consistently criticized McCain for supporting the original Iraq invasion, which polls show many voters now consider a mistake. Obama, who has made Afghanistan a centerpiece of his anti-terrorism strategy, has said the protracted Iraq conflict has drawn needed resources away from Afghanistan where al-Qaeda and Taliban forces have shown a resurgence.
He also said Saturday while beginning a weeklong vacation in Hawaii that McCain's embrace of President George W. Bush's policies shortchanged Americans by favoring an extended war in Iraq at the expense of fixing underfunded schools and crumbling roads and bridges.
Obama used a national radio address to trumpet his campaign proposals to end U.S. dependence on foreign oil by investing in alternative energy and to conclude the war in Iraq responsibly "by asking the Iraqis to take responsibility for their future and to invest in their own country."
He pointed to a recent Government Accountability Office report that found the Iraqi government could end the year with a $79 billion budget surplus while spending only a fraction on reconstruction costs that are largely borne by the U.S.
"Sen. McCain talks about putting our country first, but he is running for a third term of the very same policies that have set our country back," he said.
Money spent in Iraq could have been used to help develop alternative energy and create jobs, he argued, "and begun to end the tyranny of oil in our time."
The two also weighed in on the fighting in the breakaway South Ossetia region, contested by Russia and Georgia. McCain said he had spoken with Georgia President Mikhail Saakashvili late Saturday and called Russia's military actions in the conflcit "totally, absolutely unacceptable."
"I would be very direct with (Russian) President (Vladimir) Putin that these actions will have consequences long term, in terms of our relationship with Russia, and it is in violation of the norms of international conduct," he said in an interview with The Associated Press in Las Vegas.
Obama said he had talked with U.S. Secretary of State Condoleezza Rice and Saakashvili to condemn Russia's recent actions. He said top diplomats from the U.S., the European Union and the United Nations should become directly involved in mediating the military conflict.
"A genuinely neutral mediator - not the Russian government - must begin a process of negotiations immediately," Obama said in a statement.
Also Saturday, Democrats met in Pittsburgh to debate the party's platform. On Iraq, the draft states that Democrats "expect to complete redeployment within 16 months." That reflects Obama's time frame, but with less certainty than he has expressed.
Party platforms are a statement of principles that are not binding on the candidates or the next president and they are typically given little attention after they are adopted.
The Democrats' platform also includes a guarantee to health care for all Americans, support of women's rights, energy rebates to struggling families, a crackdown on predatory lenders, higher taxes for families earning over $250,000, tax breaks for others, billions for economic stimulus and "direct high-level diplomacy, without preconditions," in the case of Iran.