MEXICO CITY -- For former officials Jorge Diaz Serrano and Arturo Durazo Moreno, "moral renovation" has meant years of incarceration while fighting protracted court battles over charges of corruption during the administration of former president Jose Lopez Portillo.

For Lopez Portillo, who presided over what is widely described as the most corrupt administration in Mexican history, from 1976 to 1982, the anticorruption campaign launched by his successor has meant more than four years of virtual seclusion and public repudiation. But that isolation now appears to be ending in a seemingly measured reemergence into the public eye.

Five years after Lopez Portillo's successor, President Miguel de la Madrid, made "moral renovation" a keystone of his administration, the anticorruption campaign has come in for mixed reviews. Improvements in public accountability and monitoring of civil servants have been instituted, and no major scandal has arisen, Mexican and foreign observers say.

But widespread corruption persists at various levels of officialdom, they agree, especially graft associated with the highly lucrative narcotics trade. And conflicting signals about how the anticorruption campaign should be measured have suggested that its opening salvos, such as the prosecutions of Diaz Serrano, the former head of the Mexican state oil company, and Durazo, ex-police chief of Mexico City, may be exceptions.

"Given the fundamentally preventive nature of moral renovation," de la Madrid said in a state of the union speech on Sept. 1, "we must not measure its results by the number of public servants who have been sanctioned or reported to the authorities of the Federal Public Prosecutor's Office." He said that the "real progress" lay in government's closer adherence to the law, greater accountability and increased responsiveness to citizens' demands. He said his administration has "eradicated the harmful practices of nepotism and excessive gifts to public servants," responded to public complaints of irregularities and instituted legal changes to monitor the property of high-level public servants, audit state companies, review governmental purchases and require open bidding for public works.

De la Madrid pledged that in the last year of his six-year term -- traditionally a period of the most rampant corruption in Mexican presidencies -- he would "prevent public servants from adopting indolent attitudes or engaging in illicit conduct." He vowed to "hand over accounts in good order."

According to Ignacio Pichardo Pagaza, who heads the Federal Comptroller General's Office, "There has been a very important change in the attitude and conduct of high public officials." Senior and mid-level officials "are conscious that public resources must be used only for lawful purposes," he said.

Pichardo cited new laws that prohibit conflict of interest ("a new concept for us"), bar the use of "privileged information" to obtain private profits and require annual declarations of wealth from about 100,000 ranking civil servants in the 1.5 million-member bureaucracy.

Pichardo said criminal charges were pending against 360 officials and that "administrative sanctions" had been applied in the cases of "many more." He said many findings of irregularities stemmed from tips.

"In 1982, we made a decision to recognize that we have a problem and to bring it out into the open and fight it," Pichardo said in an interview. "This had a political cost, but we took the risk. We are a society with enough maturity to admit our problems and attack them openly."

Yet, Pichardo argued, corruption is no greater in Mexico than in other countries, including many developed nations. He produced an inch-thick black binder with clippings since April from the New York Times and Washington Post on various U.S. cases, from the Wedtech affair to a two-year "sting" operation in New York and New Jersey in which public officials allegedly accepted all but one of 106 bribes offered by an FBI undercover agent. The lone exception was a case in which the public official allegedly considered the bribe too small.

The comptroller general's office was established in January 1983. Of its 1,400 persons, 1,000 employes are involved in auditing and inspecting the country's huge bureaucracy and network of state-owned enterprises, Pichardo said.

"There have been improvements in little things," Mexican economist Jorge Castaneda said of the moral renovation campaign, citing elimination of payoffs in the government agencies that process fees for autos, property taxes and water bills. "The general improvement is that people are more scared. There's more peer pressure and a feeling they're being watched over."

However, Castaneda and other sources assert that moral renovation has produced little of substance in terms of jailings of corrupt high-level officials.

"One of the disappointments of moral renovation is that they've not gone after more bigshots" than Durazo and Diaz Serrano, said a diplomat. "Moral renovation has lost a lot of credibility."

According to Ramon Garcia Gonzalez, the spokesman for the comptroller general's office, "The problem is that people expected we would put a lot of officials in jail, and they measured us by how many people we put in jail."

Today, Diaz Serrano and Durazo remain the only two major figures jailed for corruption by the de la Madrid administration, and their cases have run into problems.

Diaz Serrano, 66, was jailed in 1983 on charges that he received a $34 million kickback on the purchase of two oil tankers for the state oil company, Pemex, which he headed under the Lopez Portillo administration. In May, the dapper former oil-drilling company executive, who was once mentioned as a potential successor to president Lopez Portillo, was sentenced to 10 years in jail and fined $54 million for fraud.

Earlier this month, however, Diaz Serrano appealed the sentence, which he called "ridiculous, absurd and immoral." He said his conviction was "plagued with irregularities," notably the "violation" of his immunity as a senator.

"I had the audacity to aspire to the presidency of the republic, and for that I am now suffering the consequences of the illogical Mexican political process," he told the Mexican daily Excelsior in May. Despite what he said was a close friendship with U.S. Vice President Bush, Diaz Serrano added, he did not want any foreign intervention in his case.

In the case of Durazo, 64, the widely feared former Mexico City police chief known here by his nickname, El Negro, a prosecutor's efforts to obtain a conviction on charges of extortion and illegal possession of weapons have been complicated by the fact that all but one of more than 30 witnesses against him have recanted their testimony, and others have failed to appear in court.

So far, the lone prosecution witness to stick by his testimony against Durazo is his former security chief, Jose Gonzalez y Gonzalez, who wrote a book entitled "Lo Negro del Negro Durazo" ("The Dark Side of Blackie Durazo"). In it he accused the former police chief of involvement in drug trafficking, extortion, smuggling, embezzlement of public funds, protection of prostitution and gambling rings and complicity in the 1982 gangland-style murders of 12 Colombian drug traffickers in Hidalgo.

Durazo, a childhood friend of Lopez Portillo, was charged with the relatively minor offenses of taking about $700,000 in bribes collected by vehicle-licensing officers under his command and illegally stockpiling 150 unregistered firearms, mostly antiques.

During his tenure as police chief from 1976 to 1982, Durazo built a palatial, $2.5 million house with a discotheque, racetrack, firing range, swimming pool, 23-car garage, stables and Roman-style sculptures set amid landscaped gardens, man-made lakes and fountains. A vacation house overlooking the Pacific has been dubbed by neighbors "the Parthenon."

The de la Madrid government has turned the Durazo estate outside the capital into a "Museum of Corruption" and opened it to an indignant public.

Officials say the charges against Durazo were limited by a need to present a solid case to obtain his extradition from the United States. Durazo fled Mexico in December 1982 and was arrested by FBI agents in June 1984 as he stepped off a private jet in Puerto Rico.

According to Mexican historian Lorenzo Meyer, de la Madrid's moral renovation campaign signaled "acceptance at the very top of government that something had gone very wrong." Yet, he said, the government focused on the two "weakest links in the chain" -- Durazo and Diaz Serrano -- and ignored the most powerful, including the former mayor of Mexico City under Lopez Portillo and the ex-president himself.