Al Gore criticized the Bush administration's policy on Iraq Monday, saying it has hurt the United States' standing in the international community and could dangerously undermine the rule of law around the world.

"After Sept. 11, we had enormous sympathy, goodwill and support around the world," Gore said Monday. "We've squandered that, and in one year we've replaced that with fear, anxiety and uncertainty, not at what the terrorists are going to do but at what we are going to do."

A senior administration official told Fox News "the president has unified the nation and the nation has rallied behind him. He will continue to lead the nation even if splits start emerging within the Democratic Party and its presidential candidates."

In his first major speech on the Iraq situation, Gore, the once and possibly future Democratic presidential candidate accused President Bush of abandoning the goal of a world where nations follow laws.

"That concept would be displaced by the notion that there is no law but the discretion of the president of the United States," he said.

"If other nations assert the same right, then the rule of law will quickly be replaced by the reign of fear," and any nation that perceives itself threatened would feel justified in starting wars, he said.

Gore also told an enthusiastic Commonwealth Club crowd he would decide in December whether to challenge Bush again for the presidency in 2004.

Republicans quickly pounced on the speech as evidence of Gore's weakness.

"It seemed to be a speech more appropriate for a political hack than a presidential candidate by someone who clearly fails to recognize leadership," said Jim Dyke, a Republican National Committee spokesman.

Gore always has supported overthrowing Iraqi President Saddam Hussein and was one of the few Senate Democrats who voted in favor of the Gulf War resolution after Iraq attacked Kuwait. He said he felt betrayed by the first President Bush's "hasty withdrawal from the battlefield."

But like other leading Democrats, Gore has expressed reservations in recent months about military action against Iraq, suggesting the diplomatic costs would be extremely high.

His speech Monday was much more critical, warning of ominous and untold consequences, ranging from a short-term power vacuum that could increase the danger of chemical and biological attacks, to the creation of legions of enemies angry and fearful about U.S. domination.

"If we end the war in Iraq the way we ended the war in Afghanistan, we could easily be worse off than we are today," Gore said.

Gore described his speech as an effort to lay out an alternative to the course of action pursued by the Bush administration.

Even before securing United Nations support for a multinational war against Iraq, Bush asked Congress to approve the use of "all means that he determines to be appropriate, including force," in a unilateral effort to topple Saddam.

Gore urged Congress not to give the president such a broad mandate.

"It needs to be narrowed," said Gore, adding that Congress should urge Bush to go back to the U.N. Security Council and secure the "broadest possible international support" for a regime change in Iraq.

Meanwhile, Gore said, "Bush should not allow anything to distract us from the mission of avenging the murder of 3,000 Americans."

Also Monday, former President Carter criticized Bush's stance on Iraq, saying military action without the blessing of the United Nations would be a grave mistake that would put America in danger.

"I'm quite concerned" about the White House's pursuit of Saddam without the support of many of its allies from the Persian Gulf War, Carter said after a speech at the University of Virginia.

"It is a radical departure from traditions that have shaped our nation's policy by Democratic and Republican presidents for more than 50 years," Carter told reporters.

Fox News' Jim Angle and The Associated Press contributed to this report.