Republican Sen. John McCain accused Sen. Barack Obama of making ill-informed comments about Iraq and Al-Qaida at Tuesday night's Democratic debate, a sneak preview of how a general election battle between the colleagues might play out on the issue of foreign policy.

Despite McCain's war-hero status and years of foreign policy experience, Obama made it clear he will not back down from such a fight and issued a quick rebuke.

The spat began when McCain seized on a comment by Obama that he would reserve the right to return to Iraq after withdrawing troops "if Al-Qaida is forming a base in Iraq."

"I have some news," McCain told voters at a rally in Tyler, Texas, Wednesday. "Al-Qaida is in Iraq. Al-Qaida is called Al-Qaida in Iraq. My friends, if we left, they wouldn't be establishing a base ... they would be taking a country. I will not allow that to happen, my friends."

Speaking to 7,000 voters at Ohio State University, Obama answered McCain's mocking tone with his own.

"I have some news for John McCain, and that is that there was no such thing as Al-Qaida in Iraq until George Bush and John McCain decided to invade Iraq," Obama said, as the crowd roared their approval. "I've got some news for John McCain. He took us into a war along with George Bush that should have never been authorized and should have never been waged. They took their eye off the people who were responsible for 9/11, and that would be Al-Qaida in Afghanistan that is stronger now than at any time since 2001."

The Sunni extremist group Al-Qaida in Iraq formed in response to the U.S. presence in Iraq. The U.S. military believes that the group's activities peaked in 2006 and that American forces dismantled, but not destroyed, much of the organization last year.

POLITICAL ROUNDUP

MCCAIN'S PANAMA BIRTHPLACE RAISES A MUSTY DEBATE

John McCain's likely nomination as the Republican candidate for president and the happenstance of his birth in the Panama Canal Zone in 1936 are reviving a musty debate that has surfaced periodically since the nation's founders first set quill to parchment and declared that only a "natural-born citizen" can hold the nation's highest office.

Almost since those words were written in 1787 with scant explanation, their precise meaning has been the stuff of confusion, law school review articles, whisper campaigns and civics class debates. To date, no American to take the presidential oath has had an official birthplace outside of the 50 states.

"There are powerful arguments that Sen. McCain or anyone else in this position is constitutionally qualified, but there is certainly no precedent," said Sarah H. Duggin, an associate professor of law at Catholic University who has studied the issue extensively. "It is not a slam-dunk situation."

McCain was born on a military installation in the canal zone, where his mother and father, a Navy officer, were stationed. His advisers say they are very comfortable that McCain meets the requirement and note that it was researched for his first bid in 1999. But given mounting interest, the campaign recently asked Theodore B. Olson, a former solicitor-general, to prepare a detailed legal analysis.

Sen. Lindsey Graham, R-S.C. and a close McCain ally, said it would be incomprehensible to him if the child of a military member born in a military station could not run for president. "He was posted there on orders from the United States government," Graham said.

NO BLOOMBERG RUN

After two years of playing coy about his presidential ambitions, New York City Mayor Michael Bloomberg declared in a newspaper opinion piece Wednesday that he will not run for president but might support the candidate who "takes an independent, nonpartisan approach."

The 66-year-old billionaire businessman, who aides had said was prepared to spend $1 billion to run as an independent, wrote in an opinion piece on the New York Times' website that he will work to "steer the national conversation away from partisanship and toward unity; away from ideology and toward common sense; away from sound bites and toward substance."

Bloomberg, who has almost two years left in his second term at City Hall, had publicly denied any interest in running for president since one of his political advisers first planted the seed more than two years ago.

But his denials grew weaker in recent months as aides and supporters quietly began laying the groundwork for a third-party campaign.

"I listened carefully to those who encouraged me to run, but I am not -- and will not be -- a candidate for president," he wrote.

ANOTHER SUPERDELEGATE LOST

Civil rights leader John Lewis dropped his support for Hillary Rodham Clinton's presidential bid in favor of Obama. Lewis, a Democratic congressman from Atlanta and a superdelegate, is the most prominent black leader to defect from Clinton's campaign. Lewis said Obama's campaign "represents the beginning of a new movement in American political history" and that he wants "to be on the side of the people."

ELLISON'S VIEWPOINT

Rep. Keith Ellison, D-Minn., says suggestions that Barack Obama is Muslim won't have any effect on his presidential candidacy.

Ellison, the first Muslim member of Congress, says that's because Americans are not bigoted and won't be swayed by such suggestions.

He says he has "no doubt" that a Muslim could be elected president.

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