Ian Smith is bitter. Joshua Nkomo, the embodiment of the jolly fat man, is now a sad, frustrated figure trying to lead his people in a no-win situation. Bishop Abel Muzorewa is simply forgotten.

After fighting for years to maintain or gain power in this war-ravaged southern African country, the three rivals now have one thing in common -- political demise at the hands of Zimbabwe's prime minister, Robert Mugabe.

For all three, the past year has been a difficult one, a time of adjustment to a new political reality: power is beyond their grasp.

Until the election of Mugabe last year, they were household names in the international press.

During 15 years of illegal independence, it was practically impossible to write a story about the country, then known as Rhodesia, without mentioning prime minister Smith. But the other day, when he entered the city's main hotel, not a head in the lobby turned.

During their days as nationalist leaders, Nkomo and Muzorewa traveled the world seeking political support.

Nkomo now spends most of his time in Bulawayo, his tribal stronghold where he is still revered. His only real role is to preach harmony between the majority Shonas and his Ndebele tribesmen.

Success will give him an honorable place in Zimbabwe's history books but is bound to mean the end of his party. Failure could lead to civil war.

Muzorewa still travels to the United States twice a year for conferences of his American-based, United Methodist Church. The Church, in effect, is now his party. Its headquarters is the only place he keeps regular office hours.

Of the three, Smith has adjusted least. His remarks in interviews are vintage Smith -- almost the same things he said for years as he fought "this thing called majority rule which was foisted on us." Despite the change of the country's name to Zimbabwe, his party still bears the mame Rhodesian Front.

The catalyst for years of international diplomacy to end his white-minority rule in Rhodesia, Smith is still unforgiving of the West and sharply critical of the Mugabe government.

In a half-hour interview he was unable to come up with a single statement praising the new black-majority government.The closest he could come was to say he "was pleasantly surprised" that Mugabe had not instituted a Marxist government and forced the 200,000 white minority to leave.

Asked if he could think of anything positive the government had done, he replied: "Not offhand. I don't walk around with a list of use these things."

There was no mention of expanded educational opportunties and free health care for poor blacks or of the establishment of a minimum wage.

The best he could say was that "one has to to give them more time . . . It's early days." The crunch," he said, would come this year, which he termed a year of decision.

He was sharply critical, however, of what he regarded as antiwhite attitude and inefficient government.

"I think there's quite a lot of inefficiency in government at present because we are being governed by people who know nothing about government."

He attributed the alleged ineficiency to the departure of thousands of whites and the "promotion of people just because they are black."

The exodus of whites he blamed mainly on "a few of the wild people" in Mugabe's government who "go out of their way to make the white man feel unwelcome, hurling insults of the past white colonial regime."

Africans, he added, should be "grateful" for the country's past history since "they are betteer off than any other blacks on the African continent. They've got no grounds for complaint."

"Most of the countries [in Africa] are bankrupt," he said. "They have starving people. We hope we can avert that. If there is mismanagement in government, we may go the same way. We hope not."

Smith has not relented on any of his past positions. He showed no regret for the decade-long imprisonment of Mugabe and Nkomo, saying, "There are worse things than being in prison; people were killed. Prison by comparison was mild."

He also sought to absolve himself of responsibility for the detentions, saying he did not make the decisions on jailings. They were made by security officials, he said.

As usual, some of his sharpest criticism was leveled at the West, which "supported the Russians" in the country's seven-year guerrila war.

He called the Carter administration "a bunch of starry-eyed idealists who spend most of the time dreaming about a world in which everybody played by the rules of the game."

"The United States was taken for a ride under Carter," he said, adding that if Ronald Reagan had been elected president four years ago and followed his "pragmatic" policy, the Rhodesian Army could have won the war and imposed a more favorable settlement.

The former prime minister said he would like to get out of policies, but he has mad little headway in doing so.

His Rhodesian Front Party, which for years ruled the country virtually as a one-party state, controls all 20 white seats in Parliament, which are guaranteed in the constitution. However, earlier this month, one member, Andre Holland, quit the party, resigned his parliamentary seat and formed a new white party to oppose the Rhodesian Front.

The front, he said, was carrying out a negative function in Parliament and attempts by himself and others to reform it from within had failed. The party, Holland added, has "fallen into disrepute."

Mugabe has called for for a new forum to present white interests, thus giving tacit support to the new party.

Smith's only response has been a bitter comment on Mugabe's efforts at reconciliation.

"I think the average white person in this country is looking for a little more evidence of this policy of reconciliation, which so far has been all talk and no action," he said.

Holland's move, however, reflects the deep malaise within the Rhodesian Front, which is mainly being held together by the former prime minister.

Smith says that his life has not changed much since the advent of black-majority rule.

His small office in Parliament is just a block away from where he once ruled as prime minister. The desk is bare. The phone never rang during the interview.

Only the day before a bust and a painting of Smith had been removed from the Parliament building as the government stripped it of reminders of the past.

Joshua Nkomo wept when he learnedf the results of the independence elections a year ago. It was an understandable reaction.

He had spent three decades fighting for black-majority rule, but when the day came he was rejected by his people, winning only 20 percent of the seats in Parliament.

With the vote cast on the basis of tribal loyalties Mugabe, from the majority Shona tribe, won in a landslide. Nkomo, a Ndebele, is now just the leader of a minority party with a nominal coalition role.

The situation continues to go downhill for him. While serving as the minister in charge of the police, nine of his Patriotic Front party members were arrested without his knowledge in November. In January, Mugabe unceremoniously demoted his former guerrilla comrade after two weeks of tense debate within his party. Nikomo accepted the position of minister without portfolio with the duty of helping the government in the delicate integration of his and Mugabe's guerrilla forces.

However, he has missed most of the weekly committee meetings dealing with security problems and has also failed to attend many Cabinet sessions since his demotion.

With more than 5,000 of his restive forces still armed and not yet integrated into the new national Army, he faces a cruel dilemma. He can lead his forces into a hopeless civil war or preside over their disarming and integration -- a further step in the demise of his party.

Nkomo, the consummate politician in his home area, made that clear at a fervid rally of about 50,000 supporters last month in Bulawayo.

Swinging his hefty 250-pound bulk across the speakers' platform at White City stadium, he answered complaints that his people were being badly treated by Mugabe's party.

"Whatever happens, let it be. What is important is people's rule, not the rulers."

He also told his former guerillas to take the peaceful road.

"I know some of you . . . say if things go on like this we should pick up hunting clubs. I say no. Nations are not built by use of hurting clubs.

"What is your humiliation compared to the breakup of Zimbabwe?"

Knowing that his forces are a ready scapegoat for troubles in the country, he said, "Don't let people who want to divide the country provoke you to provide an alibi for violence."

With a plea for an end to criminal acts, he pointed his tribal chieftain's stick at the crowd and said, "I'm talking about some of you . . . I don't want to lead a party of thugs."

Nkomo's problem is that he is idolized by about 20 percent of the population while most of the rest of the people have little use for him. Ironically, he and Smith find themselves in similar positions as the main bulwarks against the demise of their powerless parties.

Few analysts would put money on the longevity of Nkomo's party, in the limited role Mugabe has assigned to it.

Mugabe may prefer simply to let the party continue to atrophy as long as Nkomo, who is 63, lives.

"I'll remain active all my life," Nkomo said in an interview. "I can't imagine myself doing noting politically."

There have been increasing reports of a merger between the rival parties, but when questioned, Nkomo said, "Never."

The "never," however, sounded reminiscent of Ian Smith's claim that there would never be majority rule in Rhodesia during his lifetime.

Muzorewa says he doesn't like to talk about the brief six months when he was prime minister.

"What good does it do?" he asked.

The telephone book still lists seven numbers for his United African National Council, which won only three seats in Parliament in the elections. nNone of the numbers are functioning, however, the result of the loss of hundreds of thousands of dollars of financing from the South African government.

Muzorewa busies himself with his activities as bishop of the U.S.-based United Methodist Church. He visits the United States twice a year.

His aides say the bishop shies away from speaking in Parliament since he is jeered when he does. He denies the allegation but acknowleges that he has only made three speeches in the 10-month-old Parliament.

In a rare interview he seemed mainly concerned that history would credit him with helping to bring about majority rule. He was elected the country's first black prime minister in 1979 after making a deal with Smith that retained substantial control for whites.

The world never recognized his government and his relations with Smith destroyed his political popularity in the black community.

There is no contact between the former prime ministers.

"I don't believe I'll ever meet with Smith again," Muzorewa said. "He's bitter toward me because we" agreed to changes in the constitution curtailing white control at British-sponsored peace talks in London in 1979.

If he had not gained power from Smith, Muzorewa said, there would have been no peaceful settlement. "It would have been war to the bloody end."

"We ploughed a lot to prepare for a democratic country," he said.

Although critical of Mugabe's policies, he did tell his supporters at a rally: "Everyone who is fair and honest, who doesn't have a biased and twisted mind, [will] recognize and accept that over the past year we have witnessed a number of improvements in our lives and in our land."

For that, he said, they should thank his successor.