WASHINGTON – President Bush’s nominee to be the nation’s first intelligence director promised fundamental changes at the 15 agencies he’ll oversee and said he would give policy makers the “unvarnished truth” about threats.

“Our intelligence effort has to generate better results. That’s my mandate, plain and simple,” John Negroponte, a veteran diplomat and former Iraq ambassador, told the Senate Intelligence Committee at his confirmation hearing yesterday.

Democrats, still chafed by the botched intelligence on Iraq, said they were skeptical he could be the independent arbiter of intelligence the nation needs and questioned whether he adequately reported human-rights abuses as ambassador to Honduras two decades ago.

Senator Wyden, a Democrat of Oregon, said Mr. Negroponte’s 1980s-era declassified communications suggest he was “an ambassador to a different country” and “saw things through an administration-colored lens.”

Yet Mr. Negroponte, backed firmly by the committee’s Republicans, repeatedly tried to assure senators of his objectivity.

“My punch line is, I believe in calling things the way I see them, and I believe that the president deserves from his director of national intelligence and from the intelligence community unvarnished truth,” he said.

Mr. Negroponte’s confirmation is expected to win easy approval by the intelligence panel and the full Senate.

That would make him the first national intelligence director, charged with overseeing the government’s 15 highly competitive spy agencies. The job that Congress created last year represents the most sweeping change to the intelligence community’s leadership since 1947.

Mr. Negroponte will take over a spy community that has become known for the bureaucratic infighting detailed by a number of recent blue-ribbon commissions that examined the attacks of September 11, 2001, and the intelligence errors in the run-up to the Iraq invasion. Dozens of reforms have been proposed.

However, Mr. Negroponte frustrated some Democrats by declining to provide an outline of changes he’ll make, saying he is still studying the commissions’ findings.

Instead, Mr. Negroponte for the first time laid out his broad vision for American intelligence. He acknowledged that he must bring together “fiefdoms” at the Pentagon, CIA, Justice Department, and Homeland Security Department and said part of his job will be to ensure officials are not risk-averse against an eclectic array of enemies.

“We need a single intelligence community that cooperates seamlessly, that moves quickly and that spends more time thinking about the future than the past,” said Mr. Negroponte, who called this his toughest assignment in a 40-year government career.

Senate Intelligence Chairman Roberts, a Republican of Kansas, said he wants Mr. Negroponte to provide leadership and “a kick in the pants when necessary” to intelligence agencies. But significant doubts have been raised about whether Mr. Negroponte will have enough authority under the law to rein in the often-insular CIA and the defense secretary, Donald Rumsfeld.

Nervousness has already emerged about an internal Pentagon proposal to consolidate intelligence activities under a single official, Defense Undersecretary Stephen Cambone, which has been interpreted by some as an effort to control access to defense intelligence.

Mr. Negroponte said the move would not preclude his ability to work directly with the defense intelligence agencies, such as the code-breakers at the National Security Agency, and said the law gives him “substantial authority” that he can stretch “to the utmost.”

Senator Levin, a Democrat of Michigan, said he’s too often seen the senior intelligence leaders “exaggerate or misrepresent” information to support the White House. Mr. Levin has been particularly critical of George Tenet, the former CIA director, who called the case against Saddam Hussein a “slam dunk.”

Illustrating the breadth of issues that Mr. Negroponte faces, senators asked how he’d deal with issues of foreign detainees abused in American custody and whether he’d allow the transfer of prisoners to other countries for interrogation – where critics say they might be tortured.

Mr. Negroponte vowed agencies would be in “full compliance” with the law.

Mr. Negroponte, the father of five adopted Honduran children, has held the ambassadorships to the United Nations, Mexico, and the Philippines.

However, his 1981-1985 tour as ambassador to Honduras during the Reagan administration has repeatedly arisen as a sore spot. Yesterday, he told senators that his actions there “were always entirely consistent with applicable law at the time,” including a congressional amendment that cut off funds for the Contras, which Reagan administration officials violated as part of the Iran-Contra scandal.

Human rights groups have also alleged that Mr. Negroponte acquiesced in abuses by Honduran death squads, funded, and partly trained by the CIA. Mr. Negroponte said Honduras was surrounded by civil wars, but its record compared favorably to neighboring countries.