FOR MORE THAN seven months Post reporter Leon Dash trekked across the vast reaches of southern Angola, guided by guerrillas of UNITA. This group lost out in the civil war attending the birth of independent Angola last year but lived to fight on. Mr. Dash found that, though the government may control the towns, UNITA exercises effective control of the Texas-sized countryside and enjoys broad popular support among the Ovimbundo people, the dominant tribe in the south and the largest one in the country overall. UNITA leader Jonas Savimbi now intends to form a conventional army "to fight the Cubans," who stick to the towns; by his count they have lost 1,000 men since the government of Agostinho Neto took power. The war, a spasmodic but savage affair, could go on indefinitely, reporter Dash believes.

So much for the "Soviet stronghold" that, in 1975, American officials claimed Angola would become if the Congress halted secret support for the anti-Neto forces, as it did. Without depending on the United States, and with his nationalist credentials perhaps enhanced for it, Mr. Savimbi has stayed in the field. And not only UNITA in the south but FNLA in the north gnaws at the government's territory and prestige. Mr. Neto recently suffered the embarrassment of having to ask for more Cubans to keep him in power. Even so, late in May a coup was attempted against him, by an ex-minister purporting to be more pro-Soviet than he.

In February Mr. Neto asked the new American administration for recognition. For whatever reason, the administration hung back from responding. Thus the Russians and Cubans got the opportunity to demonstrae the ineffectiveness of their patronage. Now, with the Luanda government obviously not meeting the basic tesst of controlling the country, recognition has receded further into the future. We would say that American policy is of little relevance to the situation in Angola. The Portuguese bequeathed Angolans a broken country unprepared to govern itself as a unitary nation. The tribes and regions are fighting it out. Against this struggle, an effort to establish influence with any of the factions seems out of place and unnecessary. The United States can do little more than express its sympathy for the anguish of Angola - from the sidelines.