As the open of major legislation he has sponsored in his 11-year Senate career drifts slowly but steadily toward repeal. Sen. Harry F. Byrd Jr. of Virginia muses on its fate with all the apple-cheeked aplomb of a man who polled 57 per cent of the vote in a three-way race last fall.

"It gets back to tactics in my view," he said. "Here the President wants this done. He's a new President and many want to go along with him."

What the President wants is repeal of the 6-year-old Byrd amendment permitting the U.S. to import chrome from Rhodesia despite United Nations sanctions against trade with that country. It looks like the President will get what he wants.

Byrd thinks that's too bad ("it's a desirable and appropriate measure") but admits to no sense of personal loss for his only major bill.

"I don't take these things personally," he said. "If I took everything personally, I'd have been out of this business a long time ago."

The Rhodesian chrome fight is a small issue, but there are those who love it.

Blacks and Senate liberals see it as a battle over tacit - and in their view immoral - U.S. support for the white minority government of Rhodesian premier Ian Smith.

Hard-line conservatives see it as a war over a raw material vital to U.S. defense and as an ideological war against communism in Africa.

Somewhere between those two poles lie the Rhodesians themselves - less interested in chrome at this point than in political support in Washington - and Sen. Byrd, who happened on the issue 10 years ago at the height of the Vietnam war.

The chrome fight provides a rare public view of Byrd, a low-profile independent senator who left the Democratic Party in 1970 rather than sign a loyalty oath and has quietly cultivated the image of a lonely voice of integrity crying in the wilderness of congressional cant.

"We certainly have an uphill fight," said the courtly, white-haired Virginian smiling serenely, hands folded in his lap, from the depths of a wing-back chair in his office. "We've had a tough fight every time.

"Well, all I can do is make my own views known and each member will have to make his own decision. I have no organization like the State Department has . . . like the President has . . ."

You're just a simple country boy from Winchester, right, senator?

"That's right!" he smiled, eyes a twinkle. "That's right!"

Byrd's involvement in the Rhodesian issue goes back to January, 1967.

In those days he was a Democrat, just six months past a party primary he came within 6,000 votes of losing. There was widespread resentment in Virginia over his having been named to fill his father's unexpived term, and now the older Byrd was dead and the venerable Byrd political organization in Virginia lay in tatters.

The senator himself faced another election in just four years and badly needed the sort of political stature he never seemed to acquire during his father's lifetime, despite long years in the Virginia legislature.

He found it, as so many Southern senators do, in the mantle of national defense.

"He was shopping for a hawk issue that would fly," said a former Byrd staffer who was with him at the time. "Rhodesia was a target of opportunity."

One of Byrd's most trusted advisers was Adm. Thomas H. Moorer, then chief of naval operations, later chairman of the U.S. Joint Chiefs of Staff and a highly visible supporter in Byrd's re-election campaign last fall.

With Moorer's encouragement, Byrd began a series of speeches and letters criticizing European nations (particularly "the socialist government of Great Britain") for allowing ships flying their flag to trade with North Vietnam.

"My contention was that if we were going to get the war over with in a reasonable time, we had to shut off supplies to the port of Haiphong," Byrd said. "So it goes back to that point."

His efforts focused principally on pushing for U.N. trade sanctions against North Vietnam. He noted that such an embargo had been voted against Rhodesia when she separated from Britain in 1965, under U.N. charter provision governing action against aggressor nations.

Was Rhodesia, Byrd asked, more a threat to world peace than North Vietnam?

Byrd's Vietnam arguments were largely swallowed up in the wider nationwide debate over the wisdom of the war itself.

His Rhodesian arguments, however, were not - at least not in Virginia. Byrd-backing tobacco men in Richmond, many with business interests in tobacco-growing Rhodesia, were sympathetic to the African nation's plight.

The Richmond newspapers ran articles comparing Rhodesia to the old Confederacy - as a nation forced to independence and then persecution because of a racial situation others could not or would not understand.

Byrd said he has always believed it "unwise and unjust to put sanctions on a friendly who feel . . . that once the (U.N.) Security Council acts that becomes the supreme law of the land. I don't take that viewpoint. I think that's a ridiculous viewpoint...

"My position," he said, "has been that whatever the problems are between Great Britain and Rhodesia . . . the United States should not get involved."

He got little active sympathy for that view until it was wrapped in the chrome-plating of national security.

Rhodesia holds more than two-thirds the world's supply of chromium - an element whose properties of high-temperature strength and corrosion resistance make it essential for the manufacturer of stainless steel used in missiles, submarines and other space weaponry. The other major suppliers of chrome are South Africa and the Soviet Union.

Calling it "dangerous" and "riduculous" for the United States to increase its dependence on a potential adversary for a strategic material, Byrd in 1971 introduced a bill to end teh 5-year-old U.N. inspired embargo on Rhodesian chrome.

The bill itself, Section 503 of the 1971 Military procurement Act, made no mention of either chrome or Rhodesia. It said simply that if the United States imports a strategic materialfrom a Communist country, it can't refuse to import it from a non-Communist country. The only material covered by that language was (and still is) Rhodesian chrome.

Byrd said he was actually surprised the bill got through Congress: "I thought I had maybe a 50-50 chance," he said. Since then the Byrd amendment has survived regular and repeated repeal attempts by closer and closer votes.

Many in and out of Congress have been surprised the amendment has survived as long as it has. One aide to a relatively liberal senator said it wasn't due solely to Byrd.

"A lot of people who have looked into the Rhodesian situation have come to the conclusion that the Rhodesians have been made victims of their own rhetoric," he said. "Racial repression there is more apparent than real and Smith's government has agreed to majority rule. The recent arguments have only been over timing.

"Some of these senators don't want to destroy the country's economy before the blacks have a chance to run it, but they haven't wanted to appear to be voting for Ian Smith or thumbing their nose at the U.N. The Byrd amendment gave them a chance to do so under the umbrella of national defense."

The national defense argument was dealt a blow earlier this month when spokesmen for the steel industry testified that new metallurgical processes make possible the manufacture of stainless steel with less dependence on high-yield Rhodesian ore.

That leaves Byrd facing his critics who, citing his long-time opposition to civil rights legislation, charge that Byrd's Rhodesian amendment allows him - as one Senate staffer put it - "to holler 'Nigger!' while wrapped in the flag."

Byrd, with the turn-the-other-cheek gentility with which old line Virginia politicians traditionally disdain such talk, smiles and says "Well, they can say that . . .

"It's not my policy to assign motives . . . but they can assign whatever motives they wish me. Still, it's mvery unjust accusation. I alone didn't put the Byrd amendment on the books. It was enacted into law by the votes of representatives from 46 of the 50 states...

"If there is objection - and there is - to Rhodesian racial policies . . . the hyprocrisy of (the repeal attempt) is that it wouldd make us more dependent on South Africa which has more severe racial policies than does Rhodesia . . ."

There ware some who say that Harry Byrd has actually had less to do with the Byrd amendment and its long life than the Rhodesia lobby and its allies, who include representatives of the Foot Mining Co., Union Carbide Co., conservative commentator Fulton Lewis 11 and others. Byrd, however, says the real Rhodesian lobby is the people.

"I feel very strongly we are making a great mistake (with the repeal), not just from defense but from the cost of living.

"Even those who want repeal testifield recently before the Foreign Relations Committee that the cost of (stainless steel) products are going up if the Byrd Amendment is repealed . . .

"I think the people support the Byrd amendment" he said, and it may come back "when the price of various products go up we may find ourselves in an awkward position here. The public itself might demand it."