He looks a bit like a rumpled country lawyer. But Argentine President-elect Raul Alfonsin is as much at home in the sophisticated parlors of Buenos Aires's chic Barrio Norte as he is in the dusty provincial town of Chascomus, 66 miles south from here, where he was born and raised - and still lives.
It was this ability to fit in that Argentine political analysts say was at least partially responsible for his gigantic win in presidential balloting two weeks ago. He surprised just about everyone, himself included, with the size of his victory.
Now, as Dr. Alfonsin savors that victory and has returned from a few days' rest in his beloved countryside, he says the surprises are far from over.
Although the Cabinet he named last week was no big surprise, containing many Radical Party veterans, Dr. Alfonsin promises a Franklin Roosevelt-like 100 days after taking office Dec. 10.
''Nothing else will do,'' he says. ''The Argentine is tired of the old promises, the politics of the cheap insult.''
His program for those 100 days, however, has yet to take shape. He indicates that bringing down inflation is the first priority in the economic field - although neither he nor his economic team headed by Bernardo Grinspun say how this will be done.
Inflation is expected to top 500 percent for the calendar year and is soaring at the moment at about 900 percent. Alfonsin's one assurance so far on inflation is that his administration will not introduce ''recessive measures.''
The President-elect's ideas on reducing Argentina's $40 billion foreign debt (the third-largest in Latin America) are more specific. He says the country will repay ''all legitimate debts,'' but that the debt will be renegotiated with terms ''compatible with our condition.'' He edges toward the view that the debt is not simply a matter between a nation and a bank, but rather one between nations.
He suggests that interest rates are going to be lowered, saying, ''We are not going to accept recipes for recession, nor are we going to pay usury.''
He has specific plans for dealing with the military, which is relinquishing control 71/2 years after it took over in a coup. His plans include ''drastically'' reducing its size. He also favors abolishing the draft, diverting millions of dollars from ''wasteful'' military spending into social programs, and submitting the armed forces ''to the rule of a civilian commander in chief.''
Whether Alfonsin can get away with these curbs on the military depends in some measure on whether military officers accept his big election win as a repudiation of military rule.
The President-elect thinks the military will get the message, although he is well aware that military figures have seized power from every elected government since 1952.
''There will be no more military coups,'' he forecasts. In part he bases this prediction on his belief that the military is ''badly demoralized'' after its defeat against Britain last year over the Falkland Islands.
Alfonsin was one of the few Argentines who openly questioned the wisdom of Argentina starting that conflict with its invasion of the islands. But like most Argentines, he strongly believes the islands should belong to his country and pledges to try to make them so.
Alfonsin says he favors negotiations with Britain on the issue, but that Argentine sovereignty over the islands must be accepted. On other foreign policy issues, he:
* Accepts the Pope's proposal to resolve the Argentine-Chilean conflict over the Beagle Channel, ''with the condition that the bioceanic principle is accepted: Argentina in the Atlantic and Chile in the Pacific.''
* Opposes current US policy in Central America. He adds that ''we are no longer in an era of gunboat diplomacy.''
It is clear, however, that Alfonsin's main priorities are at home.
He says he is studying a modification of labor legislation that ''would democratize'' labor unions. Such a step will almost certainly be opposed by the Peronista movement, which lost heavily to Alfonsin's Radicals in election.
But with the labor unions dwindling in size and with the Radicals' victory, Alfonsin may be able to move on this front. The new leader specifically wants ''free elections in all labor unions'' - a step that would undercut the Peronista-dominated unions.
But Alfonsin continues to hold out the olive branch to the Peronistas. He says he stands by his election night statement to this reporter that ''we have won and won big but we have not defeated anyone,'' in what is an obvious effort to heal political divisions ''I know exist.''