Michael Kelly was fired as editor of the New Republic yesterday after owner Martin Peretz decided he could no longer tolerate Kelly's relentless attacks on President Clinton and Vice President Gore.

"The chasm between Mike's opinions and mine, and Mike's opinions and those of other editors, was both wide and increasingly deep," said Peretz, a close friend of the vice president for three decades. "There was no other voice on the Clinton administration but his."

Kelly said the firing-by-phone came days after he refused to publish an unsigned item by Peretz saying the latest allegations of improper fund-raising by Gore were "overblown and old news." Kelly added: "I didn't think that should be our editorial position. I wrote him a memo saying, Here's why I think you're wrong and I'm right.' "

He said there were also management issues on which Peretz "felt I had gone against his will, whether we run this or that. We have had our disagreements. I regarded them as operational and not a big deal, and I guess he didn't."

A former New York Times reporter and Washington correspondent for the New Yorker, Kelly had been running the magazine for just nine months. Peretz named Charles Lane, a longtime New Republic writer and former Newsweek correspondent, as Kelly's successor.

Kelly's ouster was greeted with glee at the White House. He wrote the magazine's "TRB" column, which was carried by The Washington Post and which he used almost weekly to bash Clinton as a spineless opportunist and recount the latest twists of the Democratic fund-raising scandal. Breaking a long New Republic tradition dating back to the late John Osborne, Kelly hired no one to write the "White House Watch" column.

When Peretz gave him the news, Kelly said, "he mentioned specifically the subject of Clinton scandals and that I had written so many columns about that and he didn't like that." On Gore specifically, Kelly said, Peretz "had expressed to me in the past some concerns on that subject." But Peretz said he "never actually had words" with Kelly about Gore, and "encouraged him to cover the vice president."

There have been public hints of such disagreements before. In March, when Kelly criticized Gore for having made fund-raising calls from the White House, the same issue contained an unsigned Peretz item dismissing the "tizzy of moral outrage." In a subsequent signed column, Peretz said that "Al Gore . . . does not cut corners, ethically or intellectually," but that "a scandal-hungry press" was depicting him as "a Clintonian figure."

Peretz, who lives in Cambridge, Mass., and holds the title of editor in chief, has been close to the vice president since Gore was his student at Harvard in the late 1960s. In a strikingly tepid editorial endorsing Clinton's reelection, the New Republic hailed Gore as "a genuinely serious man with a view of the future both bolder and more nuanced than any other person in our public life. He will, we hope, increasingly define the nature of a second Clinton term."

Kelly, 40, the son of a Washington newspaperman, said it is "simply not true" that he kept other political voices out of the magazine. He said he viewed the New Republic as a "big tent" and has run "all sorts of articles I didn't agree with." In one case, he said, he declined Peretz's suggestion that a certain staffer write about the Senate fund-raising hearings because that writer was busy and lacked the proper "expertise."

In bucking the boss, Kelly said, "there have been a number of occasions on which it has occurred to me I was risking my job."

One New Republic insider described the staff as depressed: "People feel they can't write about Gore. If they write pro-Gore pieces, they look like Marty tools. If they write anti-Gore pieces, they'll face Marty's anger. A lot of us feel it's an unacceptable way for a political magazine to be run."

While the 83-year-old magazine is a famously contentious place, Peretz is said to have viewed Kelly as a headstrong man who turned every argument into a matter of principle and didn't care what others thought.

Kelly already has one offer of employment from journalism's conservative wing. "He's a little tougher on Clinton than me, but I won't hold that against him," joked William Kristol, editor of the Weekly Standard.

Fred Barnes, a former New Republic writer now at the Standard, said Kelly "had started to turn the magazine around, to make it more interesting and more politically relevant in Washington. It had lost some of its salience in the political and journalistic community."

Debra Durocher, a former New Republic assistant managing editor, said that "the moment Mike stepped into the job, the atmosphere changed for the better."

But liberal journalist Eric Alterman says Kelly made the magazine "nasty," that "Marty Peretz is a neoconservative, but he always had the good sense to hire someone way to the left of him because he knows his base is a liberal base. What he hired in Michael Kelly is just a more talented version of himself."

Alterman got a taste of Kelly's temper when, after trashing him in a piece for the Nation, he accidentally took a call from Kelly meant for someone else. Alterman says Kelly took the opportunity to "start screaming and cursing" and "I finally had to hang up on him."

Lane, 35, a Harvard graduate, has worked on and off for the magazine for 14 years, with a six-year detour to Newsweek, where he covered Central America, served as Berlin bureau chief and wrote from New York. A specialist in defense and foreign policy, he missed most of Kelly's tenure while on a journalism fellowship at Yale Law School that ended in June.

Lane said it was "too early to talk about big, radical changes. I'm going to take time talking to people on the staff. The most important thing is to have a very strong connection with our readers and put out the best political magazine there is. . . . I really love the New Republic magazine. I've devoted most of my career to it. I have a very strong feeling of the place as an old institution in America."

Asked for his view of the Clinton administration, Lane stressed the need for fairness but said that "we will not shrink from taking shots at anyone when it's deserved."

Peretz called his new editor "a tested and seasoned reporter and a gifted conceptualizer as well." The benefits of office were quickly apparent: Peretz changed next week's cover to a piece on Haiti by Chuck Lane. CAPTION: Michael Kelly: His columns angered New Republic owner Martin Peretz. CAPTION: Michael Kelly, late of the New Republic, with former deputy attorney general Jamie S. Gorelick at the Phillips Gallery last November. (Photo ran in an earlier edition)