CHICAGO, Illinois (CNN)  -- At a debate in front of thousands of labor union activists Tuesday, Sen. Barack Obama's Democratic presidential rivals blasted him for his remarks about Pakistan.



Last Wednesday, the Illinois senator said that if it were necessary to root out terrorists, he would send U.S. forces into Pakistan without the country's approval.



"You can think big, but remember, you shouldn't always say everything you think if you're running for president, because it has consequences around the world," Sen. Hillary Clinton said during a 90-minute Democratic presidential forum in Chicago sponsored by the AFL-CIO.



Chicago is Obama's hometown, and Clinton's statement drew boos. The New York senator responded, "We don't need that right now."



Despite the frosty reception, Connecticut Sen. Chris Dodd joined Clinton in criticizing Obama. He said Obama's stance could undermine Pakistani President Pervez Musharraf, the country's military ruler, who has been a U.S. ally in the fight against al Qaeda.



"While General Musharraf is no Thomas Jefferson, he may be the only thing that stands between us and having an Islamic fundamentalist state in that country," Dodd said.



"So while I would like to see him change, the reality is, if we lose him, then what we face is an alternative that could be a lot worse for our country."



Obama jumped into the fray.



"I find it amusing that those who helped to authorize and engineer the biggest foreign policy disaster in our generation are now criticizing me for making sure that we are on the right battlefield and not the wrong battlefield in the war against terrorism," he said.



"If we have actionable intelligence on al Qaeda operatives, including [Osama] bin Laden, and President Musharraf cannot act, then we should," Obama said. "That's just common sense."



He also said Americans had the right to participate in the debate over such a key aspect of American foreign policy.



But Clinton countered by saying that while U.S. forces might have to pursue action inside Pakistan "on the basis of actionable intelligence," it was "a very big mistake to telegraph that and to destabilize the Musharraf regime, which is fighting for its life against the Islamist extremists who are in bed with al Qaeda and the Taliban."



"Remember, Pakistan has nuclear weapons. The last thing we want is to have al Qaeda-like followers in charge of Pakistan and having access to nuclear weapons."



Sen. Joe Biden of Delaware responded later in the debate, noting that the strategy Obama outlined was already U.S. policy.



"Everyone's entitled to their own opinion, but not their own facts," Biden said. "It's already the policy of the United States -- has been for four years -- that there's actionable intelligence, we would go into Pakistan." E-mail to a friend
what did he say? what was a sponsor allowed in this type of venue? what Obama do? what clinton say? Who was booed when she criticizes Sen. Barack Obama? Who should go into Pakistan?
would send U.S. forces into Pakistan without the country's approval. AFL-CIO. said that if it were necessary to root out terrorists, he would send U.S. forces into Pakistan without the country's approval. "You can think big, but remember, you shouldn't always Hillary Clinton U.S. forces
question: what did he say?, answer: would send U.S. forces into Pakistan without the country's approval. | question: what was a sponsor allowed in this type of venue?, answer: AFL-CIO. | question: what Obama do?, answer: said that if it were necessary to root out terrorists, he would send U.S. forces into Pakistan without the country's approval. | question: what clinton say?, answer: "You can think big, but remember, you shouldn't always | question: Who was booed when she criticizes Sen. Barack Obama?, answer: Hillary Clinton | question: Who should go into Pakistan?, answer: U.S. forces