The Bush administration on Sunday disputed assertions by leaders of the House intelligence committee that the United States went to war in Iraq on the basis of outdated and vague intelligence.

Senior U.S. officials said that premise would have assumed a dramatic change in behavior by Saddam Hussein (search) -- the elimination of Iraq's weapons of mass destruction since the departure of U.N. inspectors in 1998.

"I just don't think that was plausible," national security adviser Condoleezza Rice (search) said on "Fox News Sunday."

The White House defended President Bush's $87 billion request for rebuilding Iraq, and the Senate's top Republican appealed for maximum support from GOP colleagues when they take up the bill this week.

The administration's early estimate of the cost was about $60 billion, and a former Bush adviser was chastised for mentioning figures as high as $200 billion. The requested $87 billion would be in addition to $59 billion already spent.

"We did not have perfect foresight into what we were going to find in Iraq," Rice told NBC's "Meet the Press."

"The fact of the matter is ... this deteriorated infrastructure, one that was completely covered over by the gleaming pictures of Baghdad that made it look like a first-world city," Rice said. "The key here is that you could -- cannot put a price tag on security."

From Bush on down, U.S. officials made the case that war was necessary to remove the Iraqi president because of Iraq's stockpiles of illegal arms, including chemical weapons capable of use against approaching American soldiers.

But leaders of the House intelligence panel said in a letter last week to CIA Director George Tenet (search) that those claims resulted largely from fragmentary and circumstantial evidence filled with uncertainties. The Washington Post reported Sunday on the letter from Reps. Porter Goss, R-Fla., and Jane Harman, D-Calif., chairman and ranking Democrat on the committee.

CIA spokesman Bill Harlow denied the allegations. "The notion that our community does not challenge standing judgments is absurd," he said Saturday in a statement.

Six months after the war began, and three months after the administration sent a CIA team led by former U.N. chief inspector David Kay (search) to search, neither U.S. troops nor Kay's inspectors have reported finding weapons of mass destruction.

The letter reportedly cited "significant deficiencies" in the intelligence agencies' ability to collect fresh intelligence on Iraq after U.N. weapons inspectors left in 1998. Instead, the letter said, the agencies relied on "past assessments" and "some new `piecemeal' intelligence" that went largely unchallenged.

"There was enrichment of the intelligence from 1998 over the period leading up to the war," Rice said. "Nothing pointed to a reversal of Saddam Hussein's very active efforts to acquire weapons of mass destruction, to have very good programs in weapons of mass destruction. It was very clear that this had continued and that it was a gathering danger."

Secretary of State Colin Powell cited Saddam's use of poison gas against Kurdish civilians -- 5,000 died -- to put down unrest in 1988.

"Now, if you want to believe that he suddenly gave up that weapon and had no further interest in those sorts of weapons, whether it be chemical, biological, or nuclear, then I think you're -- it's a bit naive to believe that," Powell said on ABC's "This Week."

He said from 1998 until early this year, U.N. inspectors were unavailable in Iraq to draw on "and our intelligence community had to do the best they could. And I think they did a pretty good job."

Even with that gap in coverage, Powell said to assume that Saddam had no weapons of mass destruction "defies the logic of the situation over the years and what we know about this regime."

Powell urged Congress to approve the Iraqi money, but acknowledged that the $20 billion or so for reconstruction rather than military operations could be a hard sell.

Senate Majority Leader Bill Frist (search), in an e-mail to members of the GOP rank and file, wrote: "I ask that you devote your full energies to making the strong case for passing this legislation without delay."

The Tennessee Republican said, "The eyes of the world are upon us. Friend and foe alike, and especially terrorists, must understand that in the face of adversity, we will finish the job."

Frist said he expected a "small core of senators who will seek to defeat not only the funds to stabilize Iraq but will attempt to cut off funds for our troops now fighting there as well."

At the same time, he said, Republicans "must be careful to reach out to the many Democrats who will certainly join us on final passage."

Republican leaders oppose any effort to separate out the $20 billion from the main bill, calculating that few Democrats will want to oppose the entire request when so much of the money is designed to support American troops overseas.

Sen. John Edwards (search), D-N.C., a presidential candidate, said he wanted more answers from the White House before he would support the reconstruction money.

"We can't give the president a blank check under these circumstances," he told Fox. "I think until we get our friends and allies to the table, until we have them participating and helping us share the costs, so the American taxpayer is not paying for this by themselves, that it is very difficult to calculate."

Powell said in a televised interview that India, one of the countries the United States had been counting on to send troops, has decided not to largely because of "internal political domestic politics."