For years as a pictureque U.S. senator, Albert Gore of Tennessee was the quintessence of the populist shinkicker. Tell it like it is, take no prisoners.

Then, in 1970, he was defeated in his bid for a fourth term. Such a shame, friends and admirers clucked, that a man like Albert Gore just was not appreciated.

Wrong. "Since I had been turned out to pasture, I decided to go graze the tall grass," Gore said the other day.

He turned to the Occidental Petroleum Co., which retained him as a lawyer, then gave him a major corporate position. Strange chemistry, perhaps, but one of the realities of today's ideological crossbreeding between the public and private sectors.

As a senator, Gore could be counted upon to flay the corporate predators. As a private citizen, he is just one of a growing number of former members of Congress who do their flaying for the "other side," as it might be termed loosely.

Some other recent examples:

Paul Rogers, known as "Mr. Health" as chairman of a House public health subcommittee until his retirement last year, now sits on the board of Merck & Co., one of the drug firms he used to regulate.

Lloyd Meeds, another 1979 retiree, built a reputation as an environmental leader and corporate critic from Washington state. Now he represents Alaska land interests and Northwest timber firms.

Joseph Karth, a one-time labor organizer and then a Ways and Means Committee member from Minnesota, left Congress in 1977 after 18 years to set up a consulting firm. He helps businesses figure out ways to increase their exports.

Twelve-year Washington State congressman Brock Adams, a liberal who left the House to become President Carter's secretary of transportation, and then was fired, now practices law for clients he used to regulate -- among them Trans World Airlines.

No one is very surprised when a former legislator goes to work for a special interest or constituent he once looked out for in Congress. Examples of that are legion.

But it is quite another thing, or at least a little more surprising, when one of the old firehorses turns up at the side of an industry or an interest he once might have shunned.

An obvious point is that a man has to eat once he is retired from public office. A less obvious point, in a Washington lobbying and influenced-wielding atmosphere, is that it makes good business sense to hire an erstwhile critic.

For someone like Louise Dunlap, director of the Environmental Policy Center and longtime congressional lobbyist, it is a development that causes some concern.

"It's really a story of how opposites attract," she said. "A company buys into a former member's contacts -- they want a guy who knows 10 new people, even if they're hiring someone they used to disagree with. It ought to be an incentive to the young members: The more fuss they make in Congress, the more marketable they may be."

Albert Gore provides a case in point.

The tall grass in which he is grazing provides him income "in excess of $200,000 a year" as head of Occidental's Island Creek Coal Co. and as a vice president and member of the big oil firm's board of directors, Gore said recently in his Washington office, one of three he uses as an Occidental executive.

When Occidental proposed that Gore give up his law practice and join the company, he had doubts. "I told them they couldn't pay enough," he said. "But they did."

Gore sees no clash with his old values.

"As long as I had the honor to serve the public, I sought to do so in good conscience," he said. "So now I am in private business, where I seek to serve the public interest, but where I am responsible to the stockholders of a corporation."

Most former members of Congress, particularly those who now represent onetime antagonists, see themselves much as Gore see himself -- discerning and proud enough that they don't sense a conflict with old ideals.

Two Democratic liberals, former Senator William D. Hathaway of Maine and former representative James G. O'Hara of Michigan, now practive law with one of Washington's most potent lobbying law firms, Patton, Boggs and Blow.

O'Hara has represented General Motors Corps., Hathaway helped lobby for federal loan guarantees to the Chrysler Corp. O'Hara left the House in 1977: Hathaway was defeated in 1978.

"About 25 percent of my time involves lobbying," Hathaway said. "But I don't take clients I disagree with. In fact, I've refused several substantial ones . . . When this firm was working against hospital cost-contianment, I wouldn't take the case. I cosponsored that legislation in the Senate."

O'Hara said he has accepted clients whose causes he might have voted against as a House member, but none that he felt to be flatly wrong. "I voted against the Lockheed loan guarantee in congress, but we worked for Chrysler, so, yes, there are some issues on which I would have voted diffeently," he said.

In addition to his work for General Motors and Chrysler, O'Hara represents labor unions, Alaska land interests and timber firms. "I give them my time and my effort, but I don't sell them my soul," he said. "I've not really taken on a particular cause where I thought the client was wrong. It would bother me to do that."

The popular belief is that a former legislator has contacts and access that few others have, giving him a distinct advantage in pushing a point of view on Capitol Hill.

Not necessarily so, said Lloyd Meeds, who retired after 14 years in the House because he feared he would have to "become more conservative" to get reelected. He preferred to leave on his own terms.

"Actually, I've found that former congressional staff members have very good access to the committees," Meeds said. "I'm envious, but I probably have better access to legislators."

Meeds, working from law offices here and in Seattle, now represents clients he might have bearded when they trundled before the Interior Committee, where Meeds used to sit and catch flak for his pro-environment work.

"In representing Alaska and timber clients, I'm being totally consistent with my beliefs," he said. "During my last two years in Congress, I really broke ranks with the extreme side of the environmental movement."

Environmentalists do not entirely forgive Meeds for that "defection." Said a Sierra Club official: "Lloyd was a friend, ver supportive on a wide variety of liberal issues. But now he is not only on the other side, he's a leader of the other side."

Paul Rogers, who retired after 24 years as a Florida congressman, practices law in Washington and does some public speaking and teaching. He declined to talk in detail about his clients. He is on the Merck board and the board of the Rand Corp.

"I'm not doing any lobbying. Just law work," he said. Rogers said that some of his work involves dealing with parties that disagreed with his legislative activities. "But we always dealt with each other with respect."

Another mainstream Democrat, Fred B. Rooney of Pennsylvania, was shaken by his upset defeat in 1978. For one thing, it meant an end to his role as chairman of a House transportation subcommittee.

But his life took a nice turn. He set up a consulting business, working with railroads and other transportation industry groups over which he once held a legislative whip hand.

"I've not solicited any business -- it's all walked in the door," Rooney said.

"Today, I wouldn't take a job in Congress even if I were appointed. I thought I would miss it, but I don't. But I never would have quit, so I guess I owe the people of Bethlehem a debt of gratitude."

Like Rooney, John A. Blatnik of Minnesota, who retired in 1974 because of a heart ailment, thought he would miss the mover-and-shaker role. Not so, even though he keeps a hand in with a part-time consultancy for shippers who want federal help to keep the frozen Great Lakes open during the winter.

When Blatnik retired he was chairman of the House Public Works Committee. He was an early leader in promoting water-pollution control and economic development programs. He said that working for lake carriers was a natural outgrowth of that.

"I was invited to go to work for the road builders when I left Congress, but I didn't want that," he said. "I had to get out of the pressure-cooker." b

Floyd Haskell felt the same way as a one-term senator from Colorado. After his defeat in 1978, he stayed around Washington to practice law, write a novel and teach graduate students. He won't take on legal clients who might once have been his adversaries.

Some other liberal or progressive types who left Congress during the last decade have been less reluctant to take on controversial clients. Former South Dakota senator James Abourezk, now practicing law here, includes the government by Iran among his clients. Charles E. Goodell, Republican congressman and briefly senator from New York until 1970, has represented the king of Morocco in arms purchases. Rep. Teno Roncalio (D-Wyo.), a 1979 retiree, has energy interests among his law clients.

The trouble with pigonholing and labeling former members, said former Democratic representatie James W. Symington of Missouri, is that labels and pigonholes don't mean all that much.

Symington, a lawyer, is seen around Capitol Hill a good deal these days, lobbying for commercial river interests who want to see the government make navigation improvements on the Mississippi River.

"My law practice is uniquely distinct from my previous congressional efforts," Symington said. "But as a member of the House in 1975 I was working for appropriations for Lock and Dam 26 on the Mississippi."

"On river transportation, protection of the waterways, lock-and-dam development, we fought for that in Congress.Being from Missouri, there was never any question about the importance of the waterways."

All depends onwhere you're coming from. CAPTION: Picture, EX SEN. ALBERT GORE . . . now earning "in excess of $200,000," 1970 Photo