One turbulent year after taking on the presidency of Argentina's new democ-racy, Raul Alfonsin has moved toward a new policy course with his political fortune revived and his personal authority stronger than ever.

Only 90 days ago, the 57-year-old leader of the Radical Civic Union seemed on the brink of economic and political disaster. Inflation soared out of control while the government battled foreign creditors, the military and powerful labor unions.

Since then, Alfonsin has recorded a string of successes that have reinforced his image as a master of Argentina's volatile politics. A national strike by opposition labor unions largely failed, and attempts by military dissidents to halt human rights investigations were checked.

Late last month, the government won a resounding victory over its military and civilian opponents when voters gave overwhelming support to a peace treaty with Chile in a plebiscite. Then last week, Alfonsin's ministers finally reached agreement with foreign banks on rescheduling of the debt, even as inflation dropped to nearly half its September rate.

Euphoric Radical leaders have spent the last week talking of plans to lengthen the president's mandate and create a new "historical movement" that would match the postwar domination of Argentina by Juan Domingo Peron. "What is important here is that after a year, there is one man in control," said Dante Giadone, a ranking presidential adviser. "The president has maintained his popularity. He is a real leader, and he is showing it."

The official celebrations may turn out to be short-lived. Despite his recent gains, Alfonsin passed the anniversary of his inauguration Dec. 3 facing the same challenges as a year ago: stabilizing a chaotic economy, controlling opposition unions, and reforming the armed forces while resolving the legacy of their human rights violations.

On all these fronts, Alfonsin has been forced to redirect his policy after ambitious initial plans proved unrealistic. The result, say government critics, is that the Radical government, after a year of circumventions, is only now beginning to face its harder tasks.

"The danger that the situation could get completely out of control has passed," said Roberto Cortes Conde, a prominent political scientist. "But the government has lost a year in back and forths, trying to do the impossible, and we have to understand now that we are beginning a very difficult period."

The months ahead indeed appear perilous. After finally implementing a strict economic stabilization program in October, the Radicals appear to be courting a recession that would escalate already severe social tensions and labor unrest. In addition, the government will risk another showdown with the military in seeking civilian court sanctions of former commanders charged with human rights violations.

Even now, say many government critics, Alfonsin is not addressing his challenges realistically. "Argentina has a tremendous problem of not recognizing reality," said Jose Deheza, a former Cabinet minister of the opposition Peronist party. "And the government here is going to create a very dangerous phenomenon: its words are going to be contradicted by its actions."

Alfonsin has already shifted the scope and character of government action in the last year. After winning election on a reformist platform, he began his presidency with a sweeping series of initiatives to impose reform across the spectrum of society.

"He confronted every political power in Argentina: unions, the military, the business establishment," said Eduardo Setti, a prominent Peronist economist and politician. "Then he realized he couldn't work that way."

After a legislation regulating unions was defeated in Congress and economic pressures began to build in May, Alfonsin shifted tactics, seeking to negotiate agreements with his political rivals and construct a national alliance. Officials stalled in negotiations with the International Monetary Fund and banks, hoping to avoid tough austerity measures to cure the economy and its 700 percent inflation.

Now, many analysts here see the government moving into a new policy course necessarily stripped of more lofty ambitions. The preliminary agreements with the IMF and banks and the government's recent austerity measures, political sources say, are likely to doom any remaining prospect of broad political alliances behind Alfonsin. Instead, they say, the government will probably have to absorb the costs of implementing unpopular policies and hope that Alfonsin's own leadership will overcome inevitably strong resistance.

The president's personal flair has been the one constant of his administration. To both the wonder and irritation of competing politicians, Alfonsin has behaved as president much as he did while a candidate, crisscrossing the country to deliver stump speeches, clip ribbons and mix with crowds.

Despite widespread disenchantment with the Radical government in some sectors, independent polls show Alfonsin's own approval rating still above 50 percent. "He is still campaigning, and it has worked until now," said Oscar Camilion, a former foreign minister. "He has cowed the opposition. But he has not fully assumed the job of being a president, an administrator."

On the economic front, after nine months of bold efforts to face down the IMF and banks and stimulate rapid growth, the government was forced to shift course in September as inflation soared to a monthly rate of 27 percent and the possibility of default loomed on the $43 billion foreign debt.

Since then, sharp government cuts in spending and investments and tight monetary controls have brought inflation down to a monthly pace of 15 percent in November, or about the same rate inherited from military rule a year ago. However, the cost of the adjustment has been a plunge in retail sales and employment, and economists here now almost unanimously predict government policies will bring on a slowdown next year.

Although independent experts here say Argentina should meet the test of its IMF guidelines for the first three months of the program ending this month, some say the Radicals remain ambivalent about the stabilization program.