He seemed an unlikely compromiser to be charged with the biggest domestic issue of Ronald Reagan's presidency: tax reform. After all, it was only four years ago that Sen. Bob Packwood (R-Ore.) was deposed as chairman of the National Republican Senatorial Committee after he accused the president of snubbing blacks, women and Jews.

But by yesterday recollection had become a fine editor, as everyone from Reagan on down showered kudos on Senate Finance Committee Chairman Packwood for finally reporting out of committee a tax overhaul bill designed to bring about the biggest changes in tax law in nearly 40 years.

*"What you discover," said Packwood yesterday, moments after a triumphant press conference, "and I learned this from Russell Long years ago, is that there are no permanent friends, no permanent enemies -- just temporary alliances . . . It just doesn't do you any good to bear grudges in this business. The person who may be against you this week, you're going to need next week."

Packwood needed all the friends he could find in March, when the House sent him its version of the beleaguered tax reform bill.

From the start, much has been riding on this tax package -- for Reagan, for Republican hopes of retaining the Senate and for Packwood personally: He is up for reelection this year. Long considered a GOP maverick, Packwood, 53, found himself in the unenviable position of handling a measure that the president insisted be enacted this year, but which was being viewed suspiciously by the Senate as well as by uncountable special interests.

"I felt like assassins were after me," he said, joking about the hundreds of lobbyists who have accosted him in the past two months. "I cannot walk down the hall, I cannot take an elevator. I've had to change my route to my office. If they tell you someone is trying to assassinate you, you change your route, change cars, don't go the same way . . . I've tried to avoid direct routes so people wouldn't know where to find me."

At 11:30 yesterday morning Packwood entered a committee room jammed with those assassins: no less than 200 reporters, lobbyists and network cameras. Up to the microphones he moved, his beaming face clearly reflecting his victory.

On his way out of the press conference, Packwood said he hadn't heard from the president directly yet, but was pleased by Reagan's reaction at the press briefing in Tokyo Tuesday.

"Wonderful, wonderful . . . " said Packwood. "I mean he said they're going to have a few minor reservations. I mean, that's an endorsement."

Yesterday, administration officials were reluctant to express those reservations. Said Deputy Treasury Secretary Richard Darman, a principal figure behind the bill: "I doubt there have been five people in 50 years who could have done this."

And praise came too from one who himself had crafted the first congressional tax overhaul proposal more than three years ago. "What the committee did," Sen. Bill Bradley (D-N.J.) told reporters yesterday, "was they lost their timidity . . ."

Administration and Hill sources said Packwood moved on the bill slowly and with great deliberation, carefully handling the various interests, particularly in his state, as well as inviting individual committee members to his office for private chats. A loquacious man with a quick wit as well as a quick temper, this seems the antithesis of his reputation as a blunt-talking legislator not inclined to take guff from anyone.

"The problem is that the special interests come with two things attached: real live politicians and fundamental changes in tax law," says Darman. "The trick is to put together a package that makes sense both politically and substantively. That's a very tough trick and he managed it brilliantly."

"I was the catalyst," said Packwood, who praised Darman equally for being "not only smart but savvy" on the bill.

"I tried to know all of it better than any member knew any part of it," Packwood says, "and if I knew that, if I could be on top of every provision, it makes it a lot easier for me to make quick decisions. If some member says, 'Can you give me this?,' I think, 'I was going to give you that anyway,' so I can say, 'Well, I'll make you deal in that case.' "

Packwood is a moderate Republican who has held tightly onto his views even as the Senate has inched to the right in recent years. He has been in the Senate 18 years, and these days thinks nothing of voting against the administration whenever he's so inclined. He's more likely to be with the president on the economic issues rather than the social issues, such as abortion and school prayer.

"It's all business," he says. "Tuesday, for instance, the same day this bill goes through, I'm voting against the sale of the Stingers to Saudi Arabia."

As he ambled down the hall away from his press briefing, the assassins were again circling.

"I been telling everybody you guys are going to put together a whale of a coalition," he told two lobbyists. "When I get a question in there, 'Is the Chamber of Commerce going to like this bill?' They're gonna love this . . . "

"We're with you all the way," a lobbyist from the Grocery Manufacturers told him.

"I know, I know," Packwood said. "I think labor is going to be with us and women are going to like this bill very much and I think 70 percent of business is going to like this bill very much."

The Senate Finance Committee's version of the bill basically follows the proposal put forth by the Treasury Department a year ago. Most significantly, the bill would drop the top individual tax bracket from 50 percent to 27 percent, and the average taxpayer would pay a rate of 15 percent.

Some potentially thorny issues when the bill reaches the Senate floor: the disallowing of deductions for state and local sales taxes, as well as deductions for Individual Retirement Accounts. While the bill would retain some corporate tax breaks, it proposes to eliminate many tax shelters used by the wealthy.

"For all those people who said, 'Close those tax shelters, why isn't General Electric and General Dynamics paying?' -- they're going to pay!" said Packwood in an interview later in his office. "Why are millionaires escaping taxation? They're going to pay! It's all there."

Packwood says he expects the greatest resistance, perhaps, to come from real estate interests.

"I'll be surprised if no less than two-thirds or three-quarters, generically, of American business interests does not support this bill," he said. "You're going to have some specific groups, highly leveraged, tax-sheltered commercial real estate, which are not going to like it. Are they powerful enough to overcome the Business Round Table and Chamber of Commerce and the AFL-CIO, and National Women's Political Caucus? I don't think so."

He stands up as his phone rings off the hook and "MacNeil/Lehrer" waits, and he begins to ready himself to face his constituents in Oregon today.

"Am I relieved?" he asks with a smile. "Sure."