Outside the small town hall, armed soldiers clustered at the windows, half listening to the speaker inside, half on the alert for a guerrilla atttack. Army trucks and armored cars partly surrounded the hall, just 10 miles from the Mozambique border.

Inside, farmers clad in the traditional khaki shorts and knee socks of this area listened closely, some with rifles at their feet.

The speaker was Prime Minister Ian Smith, making a pitch for support at what may be the most crucial turning point in Rhodesia' independent history. He was appealing for votes from an increasingly divided white population that must decide in a nationwide parliamentary election on Aug. 31 whether to continue white domination or a move toward majority rule.

The group gathered at Chipinga represented two of the most important factions in this election: soldiers and farmers. Both are considered potential backers of the new opposition, the ultra-right-wing Rhodesia Action Party and - a breakaway group from Smith's Rhodesia Front Party and the most serious internal threat to the Smith government.

The wily prime minister is fighting for a solution that will lead to at least partial black rule through a settlement with two moderate nationalist leaders in a new "broadly based" government of blacks and whites. His opposition is fighting for continued white domination, as its campaign slogan - "We must indeed go forward, not blackwards" - indicates. The Action Party has charged that Smith is "planning to give away your future" by bringing in Africans. "Don't let them," the Action Party campaign literature pleads. "It's not too late to save Rhodesia."

The action party is attractive to soldiers because of its stance on the rapidly escalating five-year-old war: it wants an all-out push, including crossing the borders of neighboring Mozambique, Botswana and Zambia, to flush out Soviet-backed guerrillas.

The Action Party promiser farmers they will be able to keep their land and continue the comfortable life style that is based on domination of the African.

Many of them came from other African countries, especially Kanya, Tanzania and Zambia, after the wave of independence in the 1960s. They do not want to be "overrun" again.

Their concern and bitterness were reflected in a question asked of the prime minister by a Chipinga farmer who had immigrated from Kenya: "Why should we bring Africans into the government? They haven't proved themselves any place on this continent."

Smith, obviously aging under the strain of an increasingly tenuous political situation, has focused mainly on reassurence of the 270,000 minority whites, promising that majority rule does not necessarily mean black rule. The Rhodesian Front slogan is "No sellout," but Smith warned his audience that politics should be discussed in public during the planning stages.

Instead, he is simply laying into the opposition, charging that the Action Party is offering a solution originally devised and considered by his own party in 1963s, a solution not adequate for a 1977 problem. The Action Party basically proposes to devide Rhodesia into separate black and white areas with a federal government, a system the Action Party says will be modeled after Swiss canton, but which critics say is adapted from South Africa's apartheid policies of separate development for separate races.

The prime minister, who has dominated Rhodesian politics for more than 14 years, especially needs the votes of these farmers and soldiers to get the strong mandate needed to carry on with his internal settlement plans.

Smith's problem has been complicated by a more moderate third party, the National Unifying Force, which is contesting 18 seats. Although a fringe party, it could draw enough votes away from the Rhodesia Front for it to lose its edge.

Smith's party is certain to get to get a majority of the seats - including his own, which is not being contested by either other party - but the question here is whether he can get the two-thirds required to change the constitution.

The identifies of the candidates in this election are largely irrelevant. It is the party platforms, specifically the various solutions to Rhodesia's 12-year-old constitutional crisis and 5-year-old war, that are being voted on. At each of his stops along the border this week, Smith admitted that his audience knows more about the local candidates than he does, but added, no matter whom he was describing, that "my collegues tell me this man has two great qualities - sincerity and intergrity."

In the campaigning, it has become clear that there is little hope for the Anglo-American peace proposals to establish a legitimate government in Rhodesia, despite the diplomatic scurrying and pushing of the Western world. Once again, the majority of whites appear to prefer to go it alone.

The two key problems remain the extent of the franchise and the question of security forces under a new government. The Anglo-American proposals calls for immediate establishment of the "one-man one-vote" principle of electoral equality, which Smiht has always opposed. It would take massive guarantees for whites and special representation in Parliament for whites to get him to accept that provision.

On the problem of the armed forces, Smith had disclosed during the campaign that the Anglo-American team originally suggested maintaining the current army and sending nationlist guerrillas to other African countries for a long interim period, rather than integrate the two rival forces. Smith said he was willing to consider this solution, but the proposal was then withdrawn.

[Tanzanian President Julius Nyerere said in Dar Es Salaam that the United States, Britain and the African "frontline" states are agreed that the Rhodesian army should be dismantled when power is transferred to the black majority, Reuter reported.]

So now Smith is pushing his own solution, something between continued white domination and black rule. Smith hopes to take the first steps toward partial black rule with the cooperation of two nationalist leaders, Bishop Abel Muzorewa and the Rev. Ndabiningi Sithole, by the end of the year.

This would effect isolate the militant. Soviet-backed Patriotic Front of Joshua Nkomo and Robert Mugabe, who have the backing of the five key African "frontline" states - Mozambique, Botswana, Angola, Tanzania and Zambia - and the organization of African Unity.

Smith feels he may be able, in the end, to gain international acceptance for his solution once an election among blacks and moderate black leaders - who appear to have the support of a majority inside the country - are installed.