WASHINGTON (AP) _ The two major presidential rivals sharpened their long-standing dispute over the Iraq War. Democratic Sen. Barack Obama called it a costly distraction that must end, while Republican Sen. John McCain insisted it is a conflict the United States has to win.

"I will end this war as president," Obama said of Iraq. The likely Democratic nominee struck a stately pose as he delivered a lengthy foreign policy address ahead of an upcoming overseas trip. He spoke from a podium that said "Judgment to Lead" set up before an array of American flags.

"Iraq is not going to be a perfect place, and we don't have unlimited resources to try and make it one," Obama said in a speech Tuesday in which he also said the United States must shift its focus to defeating the Taliban and al-Qaida in Afghanistan.

Answering Obama, McCain gave his own speech in which the ex-Navy pilot, Vietnam prisoner of war and four-term Arizona senator cited his decades of military experience to paint his rival as unprepared.

"I know how to win wars," the Republican nominee-in-waiting asserted, leaving unspoken the suggestion that Obama does not. "In wartime, judgment and experience matter. ... The commander in chief doesn't get a learning curve."

McCain said Obama "will tell you we can't win in Afghanistan without losing in Iraq. In fact, he has it exactly backwards."

Foreign policy issues — the wars in Iraq and Afghanistan in particular — returned to the forefront for both campaigns even as news about the U.S. economy — the top issue for voters this year — grew gloomier. U.S. government officials were struggling to find a mechanism to rebalance America's finances that have been knocked severely out of whack by soaring energy costs, liquidity shortages among investment firms and banks, climbing food costs and increased unemployment.

Obama said he would send about 7,000 more troops to Afghanistan, the landlocked country that was an al-Qaida haven at the time of the Sept. 11, 2001 attacks. McCain said as many as 10,500 additional troops were needed but chided Obama for discounting recent American successes in Iraq.

After his swift response, McCain sought to clarify that he was not necessarily talking about sending that many American troops, saying NATO countries that are contributing forces could be called upon to increase their presence.

He further said he would employ tactics in Afghanistan akin to those used by American forces during the so-called troop surge in Iraq. Most of the additional 30,000 American troops sent for the buildup last year have now been withdrawn and violence in Iraq is at a four-year low, according to the U.S. military.

While the two men agreed on the importance of prevailing in Afghanistan, the dispute veered in a new direction when it came to the tribal areas of next-door Pakistan, where al-Qaida leader Osama bin Laden and his supporters are thought to be hiding.

McCain accused Obama of "trying to sound tough" by speaking publicly of taking unilateral action against those blamed for the terror attacks of Sept. 11, 2001.

Undeterred, Obama said, "If Pakistan cannot or will not act, we will take out high-level terrorist targets like bin Laden if we have them in our sights."

Despite his rhetoric, Obama refrained from saying the Bush administration's so-called surge in troop strength in Iraq had failed. Aides said his campaign Web site had been altered in recent days to remove references to that effect.

The two men sparred as Obama looked ahead to an overseas trip that will include stops in Iraq and Afghanistan, two countries where thousands of U.S. combat forces are engaged in combat. Given differences in age and experience between the two rivals, Obama's trip has taken on elements of an audition for a man seeking overall charge of U.S. war policy as well as foreign policy in general.