Argentina's Alfonsin takes office as Mrs. Peron returns home

Argentina's new civilian government led by the center-left leader of the Radical Party, Raul Alfonsin, will waste little time in tackling the business of government.

Argentines like to tell you that nothing ever really happens in the summer between December and March - it's much too hot. But Alfonsin has already drawn up an ambitious package of emergency laws that he wants the newly elected Congress to approve during its recall from summer recess.

''We have to move quickly in our first hundred days while we're still strong and while the opposition is weak,'' says Marcelo Stubring, a leading Radical politician.

The sweeping Radical election victory on Oct. 30 (54 percent to the Peronistas' 40 percent) is viewed as giving the new government a fair chance of dealing with the enormous political and economic problems that developed during nearly eight years of military rule.

The charismatic Mr. Alfonsin has no rival politician or military figure who can match his popularity. ''Isabelita'' Peron, the wife of the late Gen. Juan Domingo Peron, returned to Buenos Aires Friday from exile in Madrid to try to pick up the pieces of her party. Until this year the Peronistas had not lost a presidential election since their formation more than 35 years ago.

The Peronist candidate, Italo Luder, now is regarded as having been lackluster and a poor match for Alfonsin. The Peronistas have become deeply divided as a result of the bitter election loss.

Mrs. Peron has kept her post as titular head of the party while Mr. Luder has retired into the backround. But ''la Senora,'' as her supporters like to call her, is widely regarded as lacking the political acumen of her late husband and the emotional appeal of the leader's second wife, the legendary Evita.

Isabelita Peron's brief rule (1974-76) is regarded here as a disaster. It led to fierce fighting between rival Peronist factions and an acute financial crisis. She was overthrown by the military.

Observers say the Peronistas, once Argentina's major political grouping, may remain an ineffective opposition force. They add that there could in the end be an even deeper split within the party.

Alfonsin does not seem to have much to fear, at least for the moment, from the armed forces. The military became widely unpopular after the loss of the Falklands war and because of its handling of the economy. Corruption and violation of human rights are other factors in public anger at the military. Alfonsin's strident antimilitarism seemed to help him win the election.

The new President is said to be convinced he should consolidate his popular base by taking some bold moves in the coming weeks. He pledged an early repeal of the outgoing military government's controversial ''self-amnesty'' law, which would forgive military members for the torture, death, and dissappearances of thousands of Argentines after the 1976 coup.

The Radical Party has welcomed President Reagan's recent nod to human rights improvement here and its lifting of a ban on arms sales to Argentina as international recognition that the Oct. 30 vote put this country once again in the league of democratic nations. But they insist this does not let the armed forces off the hook.

''We cannot build our democracy on vengeance. Nor can we base it on oblivion. We must bring those responsible for the past to justice and establish the whereabouts of the disappeared,'' Alfonsin said Saturday.

The President has hinted he would like the judiciary to focus its examination of human rights abuse onthe leaders of the military juntas and other ranking officers, rather than taking sweeping judicial actions against military men of all rank.

But he may face pressure from human rights groups and Argentine congressmen for this. They want Congress to establish a special committee to investigate rights abuses and to condemn those guilty.

The Radicals' military reform calls for a reduction in the numbers of high-ranking officers, civilian control of the military-industrial complex, and a gradual phasing out of obligatory military service. The military would be replaced with a tighter corps of professional troops.

The Radicals say they will make more funds available for welfare by reducing military spending from 5 percent of Argentina gross domestic product down to 2 percent. Such a target means the new civilian government will not be in a great hurry to make major weapons purchases from the US, although there may be an interest in getting spare parts for existing equipment.

Over the weekend there were signs of fresh developments on the Falklands front, with British Prime Minister Margaret Thatcher and Alfonsin making some significant gestures of reconciliation. Alfonsin maintains his claim of sovereignty over the islands but is expected to take a somewhat more moderate tone on this highly emotional issue here if Britain agrees to resume negotiations.

The Argentines hint they could start by declaring a formal end to hostilities if London reduces the 150-mile exclusion zone around the islands and freezes development of the new military airport in Port Stanley.

On the economic front, the Radicals face the daunting prospect of rescheduling about $17 billion of payments on the country's $40 billion foreign debt and reducing a record annual inflation rate of 400 to 600 percent.

In weekend meetings here with Vice-President George Bush and State Department officials, Radical officials are reported to have repeated their commitment to honoring debt obligations. In turn, US officials are reported to have offered to press US banks to adopt a more flexible attitude toward Argentina's financial problems.

The Radicals are hoping to restore a measure of economic stability by securing an informal social contract with both industry and labor, trading off wage controls in return for job creation and stimulating growth.