If an extended absence abroad is one yardstick of an African leader's political security at home, then Prime Minister Robert Mugabe of Zimbabwe appears to be firmly in the saddle.
The political ruler of Africa's newest state, born April 1980, recently returned to his country after meeting with President Reagan in Washington and addressing the United Nations General Assembly in New York.
Mr. Mugabe, whose scholarly appearance and muted business suits belie his reputation as a former guerrilla leader, returned to a country that in the 43 months of its existence has successfully weathered two critical tests:
1. The relatively smooth transition from minority white rule to black-majority rule at independence. The smoothness surprised many Africa watchers.
2. The melding together of a united army drawn from two rival pre-independence guerrilla armies whose common objective - the elimination of the white-ruled government - was about the only thing that united them.
But compliments don't come so readily of late. Mugabe's security forces have come under sharp attack, especially from church leaders, for being ruthless in stamping out dissent among the minority Ndebele in the western region of Matabeleland.
The government's decision last month to order back to jail six white Air Force officers who were acquitted of sabotage also heightened concerns about individual rights in Zimbabwe. Mugabe defends the action on the airmen by saying the courts let them off on a technicality but that their guilt is clear. ''As a government we have to defend our security,'' he said.
Despite these rising concerns, the prime minister is still regarded in the West as a practical innovator who has successfully moved on critical fronts without jeopardizing his power base.
Diplomats recently back from Zimbabwe still see it as a land that can become a showcase for the rest of Africa.
Practically all the Zimbabwe Cabinet have traveled outside the country and taken careful notes on how to avoid the pitfalls made by some of their neighbors. The result: a more tightly run economy, strong on socialist philosophy but careful not to upset the capitalist apple cart.
Thus for all its stress on egalitarianism and social justice, Zimbabwe has not made any moves to nationalize the economy. On the one hand, it has left intact the large profitable white-run farms; on the other, it has kept the party faithful in line by moving ahead with land distribution.
This apparently zigzag course has raised eyebrows as to what ideological path Mugabe is traveling along. On some actions he is perceived as a Marxist; on others as a deeply feeling Christian.
One Western diplomat suggests that defining Mugabe in terms of East-West, North-South, or socialist-capitalist is not particularly useful. ''He is first and foremost an African nationalist. He doesn't wish to be dragged into East-West tensions,'' the official says.
In a recent address before amused Harvard University students, Mugabe chided the Western media for starting from the assumption ''that if something is not Western then it must be Eastern, therefore it must be evil.''
By his own assessment, Mr. Mugabe's own philosophy appears to favor socialism. He told the students:
''To us, man in his collective environment where he acts as one with others enjoying equal rights, both political and economic, is worth more than as an isolated individual.
''Individualism must be subordinated to collectivism, for . . . the morality of our common belongings, . . . interest, and common destiny bids us work for others as others are bidden to work for us.''
But he also concedes the economy he inherited requires Zimbabwe's ''present accommodation of private enterprise.''
While the transition to black rule and stress on socialism sparked an exodus of whites out of the country, the white population now appears to have stabilized.
Whether the trickle still leaving will again turn to a stream may depend on how successfully the government can convince the white community that the six Air Force officers are guilty of aiding South African saboteurs to blow up 13 warplanes in the center of the country last year. Mugabe admits that their confessions were obtained through torture.
The only time Mugabe bristled during his Harvard encounter was when someone asked whether the redetaining of the airmen violated human rights.
''Human rights,'' he snapped back, ''are very basic to our thinking. People who set themselves up as agents of South Africa, who kidnap tourists (a veiled accusation at his rival Joshua Nkomo's supporters) vitiate human rights and the state must take action.''
Despite adverse media comment, the issue has been treated with restraint diplomatically. Says one diplomat ''the situation legally is clouded with guilt, '' and ''at least two, and maybe three'' were definitely implicated.