(CBS/AP) Following the release of a Senate report harshly criticizing U.S. intelligence gathering and analysis, the focus will soon shift to whether and how to make sweeping changes to the intelligence community.

After a yearlong investigation, the Senate Intelligence Committee released nearly 120 conclusions about the intelligence community's performance on estimating the threat from Iraq, found primarily in a 2002 assessment that served as the Bush's administration's leading arguments for war.

After the release of the 511-page review Friday, the panel's top Democrat, West Virginia Sen. Jay Rockefeller, said three-quarters of senators would not have voted to authorize the invasion if they had known how weak the intelligence was.

"This report cries out for reform," said committee chairman Pat Roberts, a Kansas Republican.

In the unanimously approved report, senators concluded that the CIA kept key information from its own and other agencies' analysts; engaged in "group think" by failing to challenge the assumption that Iraq had weapons of mass destruction; and allowed President Bush and Secretary of State Colin Powell to make false statements.

"Most, if not all, of these problems stem from a broken corporate culture and poor management," which won't be fixed simply by giving the agency more money or people, the report said.

Among much-discussed reform proposals, some have suggested centralizing the intelligence community under a Cabinet-level Director of National Intelligence who would oversee the roughly $40 billion budget of the 15-agency intelligence apparatus. Currently, the CIA director also oversees the intelligence community, but he doesn't control the vast majority of the money.

Deputy Central Intelligence Director John McLaughlin, who said the CIA and other agencies are adapting and making internal reforms, urged caution against disruptions while the nation is in the middle of the anti-terror fight. "Some sort of reordering of the boxes here will not bring you perfection in the intelligence business," he said.

But politics may play more of a role in reforms than anything else. Few believe significant changes will happen before the November election.

The report was yet another blow to the credibility of the Bush administration and U.S. intelligence agencies. The committee concluded that key assertions used to justify the Iraq war - that Saddam Hussein had chemical and biological weapons and was working to build nuclear weapons - were either wrong or overblown.

Mr. Bush called the report a useful accounting of intelligence agencies' shortcomings. He defended the decision to go to war, however, as well as his prewar assertions about Saddam's government and weapons of mass destruction.

"We haven't found the stockpiles, but we knew he could make them," Mr. Bush said. "The world is better off without Saddam Hussein in power."

Although senators from both parties agreed in harshly criticizing the CIA, Democrats and Republicans clashed over whether administration officials had pressured intelligence analysts to reach predetermined conclusions on the Iraq threat. Democrats said there was pressure; Republicans said there were tough questions but no inappropriate influence.

Democrats also said the investigation should have examined whether the White House had twisted the intelligence it received - a second phase of the probe that probably won't be finished until after the elections.

"The fact is that when it comes to national security, the buck stops at the White House, not anywhere else," said Democratic presidential candidate John Kerry.

The report comes as Mr. Bush looks for a new leader for the intelligence community. CIA Director George Tenet has resigned, effective Sunday, and McLaughlin will take over as a temporary replacement. But the report's across-the-board criticism of the CIA could indicate that any nominee from within the intelligence community would have a tough time winning confirmation by the Senate.

McLaughlin said the CIA is learning from its mistakes and has already made changes, including adding reviews from a "devil's advocate" perspective to all future national intelligence estimates.

"We get it," McLaughlin said at a rare news conference at CIA headquarters. "Although we think the judgments were not unreasonable when they were made nearly two years ago, we understand with all we have learned since then that we could have done better."

Among conclusions in the report:

-Most major judgments in the October 2002 National Intelligence Estimate about Iraq's alleged nuclear, chemical and biological weapons programs were "either overstated or were not supported by the underlying intelligence reporting."

-Intelligence officials didn't explain to policy-makers the uncertainties behind their judgments.

-Intelligence agencies suffered from a collective presumption that Iraq had an active and growing program to develop weapons of mass destruction.

-The United States depended too heavily on defectors and foreign governments' intelligence.

In Britain, an inquiry into the quality of British intelligence on Iraqi weapons will publish its report on July 14. The inquiry, headed by Lord Butler, a retired civil service chief, aims to establish why there is such a glaring gap between "intelligence gathered, evaluated and used by the government" and the lack of evidence on the ground in Iraq.

Before the war, British Prime Minister Blair was adamant that Saddam Hussein possessed stockpiles of weapons of mass destruction.

"What I believe the assessed intelligence has established beyond doubt is that Saddam has continued to produce chemical and biological weapons, that he continues in his efforts to develop nuclear weapons," he wrote in a foreward to a September 2002 intelligence dossier, used by the government as it built its case for war.

According to British press reports, the inquiry will conclude that intelligence claiming that Iraq could launch chemical weapons on 45 minutes' notice — known to be from a single source — was vague and poorly sourced.

The British government has declined to comment.