The Roman Catholic Church, excluded violently from affairs of state after Mexico's 1910-21 revolution, may soon recover some of its former influence as a result of an olive branch offered by President Carlos Salinas de Gortari.

Attendance of church leaders at Salinas' Dec. 1 inauguration ceremony has touched off a fierce political debate, with left-wing leaders attacking the move as constitutional heresy and a threat to the separation of church and state."How can individuals dressed in religious clothes have been allowed into parliament, violating the laws on religious sects," Alfredo Reyes Contreras of the Popular Socialist Party asked in a Chamber of Deputies debate.

Church leaders, while hastening to say they are not after political power in Mexico, enthusiastically welcomed Salinas' invitation.

"(It) was an historic step forward which has broken the moth-eaten taboos of the past. We can't say that tomorrow everything will change, but undoubtedly it is important," said Geronimo Prigione, apostolic delegate of the Vatican in Mexico.

If the debate prospers, it could lead to priests voting or even running for office, and ultimately to reestablishing relations with the Vatican, broken in 1923.

The new president said in his inaugural speech promising democratic reforms that the Church should be included in plans to modernize Mexican society. Interior Minister Fernando Gutierrez Barrios last week said the government would accept a debate on the relationship between the two powers.

Such a debate, diplomatic sources say, opens up delicate issues for modern Mexico, which continues to pay lip service to revolutionary ideals that reject a church role in secular affairs.

During the revolution hundreds of churches were destroyed and priests persecuted. The church establishment, till then a powerful political force, had roundly opposed the revolution.

The 1917 constitution prohibited priests from wearing religious dress in public, taking part in politics or teaching.

In the 1920s priests and peasants led a bloody revolt which was put down by the government with hundreds of dead, a dark chapter in Mexico's history portrayed in Graham Greene's "The Power and the Glory."

But in post-war Mexico, the Institutional Revolutionary Party, which has governed since 1929, has increasingly turned a blind eye to constitutional restrictions on the church, particularly its involvement in education.

Despite the separation of the two, there is a de facto, behind-the-scenes relationship between them.

"There is no reason to keep this dialogue a secret. We must put some realism in our society without violating the constitution," Rafael Rodriguez Barrera, the party's secretary general, said.

The party, while repeatedly attacking the church for meddling in politics, is aware of its influence and that of the Virgin of Guadalupe, who is Mexico's most powerful symbol.

About 90 percent of Mexico's 85 million inhabitants are Catholic, served by 12,000 priests and 24,000 lay priests, and the calendar is peppered with religious festivals.

Encouraged by the apparent thaw in relations, the Church has asked the new government to openly discuss themes such as the right to vote and access to the media.

"We are not asking to be allowed to preach politics from the pulpit, nor become candidates in elections, but to be allowed to vote like the Mexican citizens we are," Felipe Hernandez, spokesman for the Catholic bishops' conference, said.

The fact that these reforms are being openly discussed now is a major improvement in church-state relations, which deteriorated alarmingly two years ago when the Institutional Revolutionary Party felt the church had intervened in politics by backing the center-right National Action Party during local elections in the northern state of Chihuahua.