SINCE World War II the United States has interfered in the internal political affairs of other countries on many occasions. There have been two spectacular failures, Iran and Vietnam. There have also been successes. The question is whether we can learn from the mixed record things that can be helpful in the future in deciding whether to interfere, or refrain.
Italy goes down as the most solid success. In 1947 and 1948 communism was on the rise. Washington decided to intervene. Millions of US dollars were pumped into Italy both overtly in the form of economic and military assistance and covertly in the form of election campaign funds to anticommunist politicians and parties.
The results justified the investment. Italy has become a prosperous and staunch investment - a staunch member of the NATO alliance and of the Western economic community. Italy has remained a solid friend of the US. The Italian people have supported the succession of centrist and moderately conservative governments which have ruled Italy ever since.
The US invested heavily again in South Korea. The results there have also been impressive and successful. South Korea is economically prosperous and politically stable.
Grenada, the youngest example, seems to belong on the list of successes. So far at least a majority of the people appear to be glad that they were rescued from a violent and blood-stained leftist regime.
Guatemala has a question mark over it. The US manipulated a coup d'etat there in 1954. It led to a succession of military dictatorships with one of the worst human rights records in all of Latin America. But there is at the moment a chance that the current junta will reestablish an experiment in democracy with free elections.
Why was US intervention in Italy and South Korea successful, but in Iran and Vietnam disastrous?
The difference between success or failure appears to depend on whether US intervention supports native nationalism and is supported by the native nationalist leaders. In Italy nothing is more native than the Roman Catholic Church. American aid to center and conservative political groups was always channeled in cooperation with the church and sometimes through its agencies.
The same was true, if to a lesser extent, in South Korea. But in both Vietnam and Iran the US associated with anti-nationalist forces. In Iran the prime minister, Muhammad Mossadegh, who was overthrown by American money and clandestine manipulation in 1953, was unquestionably more native than the young Shah whom the US put back on his throne.
The Shah's regime always had an imported overtone. There can be little doubt that both Mossadegh and the Ayatollah Khomeini seem to most Iranians to be more native and nationalistic than the Shah who reigned between them.
In Vietnam the very first act of American intervention was to allow the French to land a French Army for a military campaign to regain control for France of all of that which had been French Indo-China. That effort ended in disastrous failure with French surrender at Dien Bien Phu.
Washington refused to recognize the victors of Dien Bien Phu as representing native nationalism. American warships transported French-speaking Vietnamese from north to south, and in the south propped up a successor regime led by French-speaking people with a French cultural outlook. Looking back, one can see that the effort was doomed to failure from the start simply because native nationalism was on the other side.
The vital key to success of any intervention in a foreign country is whether it sides with or can enlist the support of native nationalism. Where the US has failed to appear to be on the side of native nationalism the intervention has failed. Where it supported native nationalism it has been successful.
President Reagan wants to overthrow the Sandinistas in Nicaragua.
He is on risky ground.
The Sandinistas are committed to Marxism, but they seem to have more native nationalism on their side than the contras, whom Mr. Reagan favors.