President Bush sidestepped a reporter's question Wednesday about whether he regretted basing part of his case for going to war against Iraq on information that turned out to be bogus.

Bush did not say he felt regret, nor did he explain how forged documents on an Iraqi uranium purchase could have provided the basis for remarks made in January's State of the Union address (search).

Instead, the president reaffirmed that Saddam Hussein did, at least in the early 1990s, have a program to build nuclear weapons.

"In 1991, I will remind you, we underestimated how close he was to having a nuclear weapon. Imagine a world in which this tyrant had a nuclear weapon. In 1998, my predecessor raided Iraq, based upon the very same intelligence. And in 2003, after the world had demanded he disarm, we decided to disarm him. And I'm convinced the world is a much more peaceful and secure place as a result of the actions," Bush said while at a joint press conference in Pretoria with South Africa's President Thabo Mbeki.

Lawmakers reacted cautiously Tuesday to the White House admission that Bush's State of the Union address included faulty intelligence.

But others in Washington took a more aggressive approach to the news that the White House was aware at the time of the address that documents on Iraq's efforts to purchase uranium (search) from the African nation of Niger to reconstitute its nuclear weapons program were not reliable.

"This may be the first time in recent history that a president knowingly misled the American people during the State of Union address," DNC Chairman Terry McAuliffe said Tuesday. "Either President Bush knowingly used false information in his State of the Union address or senior administration officials allowed the use of that information. This was not a mistake. It was no oversight and it was no error."

"This is the Enron (search) or the WorldCom (search) of the intelligence business. This is an absolute failure. This is an overstatement and it's embarrassing and it's very poor business for the war on terrorism, really bad news," said Col. David Hunt (Ret.), a Fox News military analyst.

Senate Minority Leader Tom Daschle, D-S.D., said the White House statement is "a very important admission" and another reason why Congress must fully investigate all the facts related to pre-war intelligence.

Daschle wouldn't go so far as to suggest -- as has Senate Armed Services Committee ranking member Carl Levin, D-Mich. -- that the administration hyped or embellished its intelligence to justify war with Iraq.

"I think it's premature to come to any conclusions about what this may or may not mean. But I think we can conclude, as Republicans and Democrats have suggested, that this ought to be reviewed very carefully. It ought to be the subject of careful scrutiny, as well as some hearings and some research with regard to what it was we knew, what actions were taken, what statements were correct and which ones were incorrect," Daschle said.

Levin has called for his staff to look at the credibility of intelligence that led to war in Iraq, but Tuesday held off on blaming the White House for the bad information.

"That is very, very disturbing as to how it is possible the CIA, or the intelligence community as a whole, did not present this information to our policymakers," Levin said.

White House officials admitted Monday that Bush incorrectly described Iraq's pursuit of uranium for the development of nuclear weapons. Bush leveled the charge while making a comprehensive case against Saddam Hussein in this year's address, borrowing from intelligence attributed to the British.

"The British government has learned that Saddam Hussein recently sought significant quantities of uranium from Africa," Bush said in his January address.

While flying to Senegal on Monday night, where the president began a five-nation tour of Africa, a senior administration official told The Washington Post: "Knowing all that we know now, the reference to Iraq's attempt to acquire uranium from Africa should not have been included in the State of the Union speech."

The president's accusation sprang from a British intelligence report that Iraq had signed a deal with Niger to purchase enriched uranium, a vital component of a nuclear weapon. But the CIA had already debunked the charge months earlier, in part through the efforts of Joseph Wilson, a career diplomat that the CIA sent to Niger to investigate the British report.

"I found that for a number of reasons the document was likely not authentic," Wilson said. "But more to the point, I found that given the structure of the uranium business in Niger, that it was highly unlikely and nigh on impossible for such a deal to go passed unnoticed."

Despite Wilson's warnings, the State Department (search) made a similar charge about Iraq's pursuit of uranium in a December press release attacking Iraq's declaration to the United Nations that it did not possess weapons of mass destruction. In the release, the State Department asserted: "The declaration ignores efforts to procure uranium from Niger. Why is the Iraqi regime hiding their uranium procurement?"

Secretary of State Colin Powell did not repeat the accusation during his U.N. Security Council presentation on Iraq's pursuit of weapons of mass destruction on Feb. 5. Officials said Powell decided the intelligence was too flimsy.

The State Department also said that it removed the Iraq-Niger accusation one day after releasing it, but the revision was only made available to U.S. embassies and until now, was never acknowledged publicly.

A British parliamentary report questioned why British intelligence endorsed what it said was clearly a dubious pact. Prime Minister Tony Blair denied any effort to trump up charges against Iraq.

"I should tell you right at the very outset, I stand by that case totally," Blair said Tuesday.

Rep. Harold Ford, D-Tenn., said he wanted to believe the president, who is supposed to have better intelligence than anyone else, but he is very disturbed by the news.

"I think it's time for [Bush] to come back before us and just explain, answer some of these questions because I trusted the president when it came to intelligence because he sees things that most of us don't see, and it turns out that not all of it was right on point," Ford said. 

Sen. Rick Santorum, R-Pa., defended the administration, saying Bush based his State of the Union address on "the best intelligence we could gather [at the time]."

Santorum was quick to point out that the administration was relying on British intelligence in this case, adding, "Obviously, when you use foreign intelligence ... you don't have as much confidence in it."

Santorum added the administration has been very forthcoming on the issue, emphasizing the fact that the administration is acknowledging the information may have been incomplete or inaccurate.

But Hunt said it's very difficult to make a future case internationally for war when the president's credibility is shot by bad intelligence.

"I think there are some people that need to be fired -- starting with the [Director of Central Intelligence George] Tenet. This is bad. When they're blaming him publicly, and that's unheard of ... it can't be glossed over. The bureaucracy has got to knock this off. It can't happen anymore," he said.

Fox News' Major Garrett, James Rosen and Julie Asher contributed to this report.