After one year in office, President Jose Lopez Portillo has restored short-term political and economic stability to Mexico, but he has been unable to stop the deterioration of living conditions for most of the country's 63 million inhabitants.

Having inherited the most serious economic crisis in 40 years, Lopez Portillo so far has focused on stabilizing the currency, slowing inflation and encouraging the resumption of private investment. In that sense, the first year of his presidency has been a success, it generally is agreed here.

With a doggedly conciliatory tone -- the exact opposite of his controversial predecessor Luis Echeverria -- he also has managed to calm the unrest among the well-to-do and the peasantry that convulsed the country in the final months of 1976.

But the euphoria that followed the end of the turmoil of the Echeverria days has given way to anguish among the middle class and the poor who have seen both the job market and their purchasing power shrinking fast.

The sharp cut in public spending -- under pressure from the International Monetary Fund -- and the accompanying recession have created staggering unemployment. Although always chronic, unemployment and underemployment now affect 53 percent of the work force, according to the government.

And an additional 800,000 persons reach employment age every year. With no public welfare system or unemployment compensation whatsoever, it seems inevitable that even more Mexicans will try to cross illegally into the United States.

But despite such ills -- the economy grew by 2.6 percent in 1977 as the population grew by 3.2 percent -- Lopez Portillo remains publicly optimistic. The crisis will be over by the end of this year and then the country can turn to "administering its progress," he said recently. The new oil wealth is regarded as the principal contributor.

In the eyes of foreign entrepreneurs, Lopez Portillo has bent over backwards to restore the faith of Mexico's conservative businessmen in government, who were driven to near hysteria by Echeverria's angry efforts to bring social reform. The president has provided business with tax incentives, scrapped a modest tax reform and stopped the Mexican tradition of giving away land to the dishevelled peasantry.

With his characteristic no-nonsense attitude, he has freely used the army and police to control student trouble in the cities and "undisciplined" peasants in the countryside, although an unprecedented number of protest demonstrations have been permitted in the capital.

Information about the fate of dissenters around the country is hard to come by. In the southern state of Oaxaca alone, almost 40 students and peasants were killed in clashes with authorities. In similar disputes over land ownership in the state of Hidalgo, 18 peasant and community leaders were jailed for almost a year.

Yet at the same time, the government has dropped charges against about 10 political prisoners, leaving close to 200 political activists or persons charged with terrorist acts behind bars, according to reports.

Despite the mounting evidence that he is slowly being pushed to the right by private-sector pressure, Lopez Portillo himself is insistent that his is not a conservative regime. He has effectively said that the economic crisis gives him no choice but to maintain an austerity program at the expense of the poor majority.In private, his aides stress that Lopez Portillo is not a conservative at heart.

Nonetheless, he has largely eliminated the power base of his close friend Echeverria and replaced progressive politicians with technocrats.

But the most striking difference in the new administration is its style. The soaring Third World oratory of Echeverria and his team has given way to the cold precepts of organization, efficiency and productivity. Instead of Echeverria's campaign for a more just income distribution and his denunciaitons of the "anti-social rich elite," the country hears Lopez Portillo hammering away at his three priorities: agricultural output, tourism and oil exports coupled with a petrochemical industry.