The White House has dismissed the proposal, saying the CIA is committed to reviewing the intelligence behind claims that Iraq had weapons of mass destruction. The Bush administration also argues that the weapons search is not yet complete.
Senate Intelligence Committee Chairman Pat Roberts, R-Kan., has expressed frustration with those who suggest an outside investigation is needed before his committee has a chance to complete an inquiry now underway. Senate Armed Service Chairman John Warner, R-Va., supports letting the committee finish its work.
In an interview with The Associated Press, McCain said he believes the public needs an assessment that won't be clouded by partisan division. The Arizona senator said he is seeking a full-scale look not only at apparently botched intelligence on Iraq's weapons capabilities, but also flawed estimations of Iraq, North Korea and Libya and the faulty assessments from other Western intelligence services.
"I am absolutely convinced that one is necessary," McCain said, "because this is a very serious issue and we need to not only know what happened, but know what steps are necessary to prevent the United States from ever being misinformed again."
McCain's comments come less than one week after the CIA's lead weapons inspector, David Kay, left his position and began stating publicly that purported weapons of mass destruction didn't exist.
The House and Senate intelligence committees that have been looking into the issue for the past seven months have unearthed failures in prewar intelligence similar to those identified by Kay, The Washington Post reported Friday.
The newspaper quoted unidentified congressional officials as saying the committees believe CIA analysts never seriously considered the possibility that Saddam no longer possessed weapons of mass destruction.
But Republicans and Democrats on the two intelligence committees disagree over whether the fault lies with the analysts or with the policymakers that used murky intelligence as a basis for war.
Democratic presidential candidates Sen. John Edwards, Sen. John Kerry, and Howard Dean also called for an independent investigation during a debate held Thursday in South Carolina.
National security adviser Condoleezza Rice reiterated that opposition Thursday, saying on national television that existing efforts to learn the extent of Saddam's weapons arsenal are sufficient while downplaying the discrepancy between prewar intelligence and what has (or hasn't) been found in Iraq.
"I think that what we have is evidence that there are differences between what we knew going in and what we found on the ground. That's not surprising. " National security adviser Condoleezza Rice said on CBS News' Early Show. "In a country that was as closed and secretive as Iraq, a country that was doing everything that it could to deceive the United Nations, to deceive the world. I would remind people that in Libya and Iran, we have found we probably significantly underestimated the significance of those weapons of mass destruction programs. So in part, this is a problem of dealing with very closed societies that are doing everything that they can to hide the extent and nature of their programs."
When asked on NBC's Today Show if she thought Americans have a legitimate concern about whether intelligence was manipulated to justify the decision to go to war, Rice replied, "The president's judgment to go to the war was based on the fact that Saddam Hussein for 12 years had defied U.N. resolutions" regarding his stock of weapons.
She added that the administration went to war, because Saddam "had been considered a danger for a long time and it was time to take care of that danger."
In a speech in Merrimack, N.H. on Thursday, Mr. Bush called the invasion of Iraq a "war for our security" and said he welcomed a debate over his reasons for launching the war, in which at least 519 Americans have died.
"We'll debate about the decision, and I look forward to those discussions with the American people," Mr. Bush said. "I'm absolutely convinced it was the right thing to do. And I look forward to explaining it clearly to the American people."
Kay and some Democrats, including Senate minority leader Tom Daschle, D-S.D., have also stated the need for an outside investigation into the intelligence community. Along with the Senate inquiry, several retired intelligence officers have delivered a review to CIA Director George Tenet on the performance of the CIA and other agencies.
McCain, who was one of the loudest voices in a successful campaign to form a commission on the Sept. 11 attacks, said he spoke to administration officials, but doesn't know what — if any — action the White House will take. McCain believes the investigation would take over a year, removing the findings from election-year politics.
McCain said the commission should consider a series of questions: Were the estimates wrong? If so, why? Who is responsible? What steps need to be taken to ensure that the president has accurate intelligence information?
Names McCain suggested for the commission include former House Speaker Tom Foley, D-Wash., former Secretary of State and Treasury George Shultz, former Secretary of State Lawrence Eagleburger and former national security adviser Brent Scowcroft.