Chileans mark the 12th anniversary of military rule here Wednesday as the opposition is expressing optimism that a new 11-party accord, encouraged by the Roman Catholic Church, may start a move back to democracy.

In the wake of antigovernment rioting last week that left 10 dead and scores more injured or arrested, opposition leaders await a definitive response to their two-week-old National Accord for the Transition to Full Democracy.

That response is expected during the anniversary speech of President Augusto Pinochet, the leader of the 1973 coup.

The accord, signed by all major opposition parties except the Communist, was announced by Cardinal Juan Francisco Fresno after several months of secret meetings between politicians and church representatives. Parties remain formally suspended or, in the case of those of the left, outlawed.

A political observer said the accord "astounded" members of the Pinochet government with a call for orderly transition to democracy that appears to have put Pinochet on the political defensive.

Although Pinochet has indirectly attacked the agreement -- which had one junta member sputtering insults, later retracted, at Fresno -- the government has left the door open to further discussion of it.

Nevertheless, the Interior Ministry announced today a six-month renewal of the emergency powers that Pinochet decreed during major protests two years ago. The 11-party accord calls for cancellation of those special police powers.

Foreign political analysts said the confused official signals reflected Fresno's success in setting a new political agenda for the return to civilian rule.

Pinochet's formula precludes any election until 1989, when the sole candidate would be picked by the military chiefs -- and could be Pinochet.

By offering the accord as an alternative, the cardinal has gone beyond traditional church mediation efforts. Its terms call for restoration of political rights and general elections at a date to be negotiated. Until that time, Pinochet's authoritarian 1980 constitution would remain in place, subject to amendments.

Diplomats and political observers here agreed that the accord was a departure from previous opposition efforts, which tended to underestimate the strength of the current rule and to present demands it found unacceptable.

This time, under the direction of Fresno, the opposition's emphasis was on compromise, a rarity among Chile's traditionally fractious parties.

Fresno, awaiting a definitive governmental response, criticized a call by leftist groups and opposition labor leaders for what resulted in a bloody day of protest Sept. 4 -- the day on which elections were held in pre-coup Chile. Fresno also called off a memorial mass for a French priest killed in demonstrations last year.

According to Sergio Molina, one of three technicians who helped draft the accord, its tone will force Pinochet to negotiate or be seen as offering as an alternative "an institutionalized version of dictatorship.

"If he ignores us, unpredictable dynamics will be set in motion, and nobody will be able to use reasonable means to stop them," said Molina, who served in a Christian Democratic Cabinet in the mid-1960s.

Seven Cabinet ministers in the government of the late Marxist president Salvador Allende, overthrown in in 1973, have announced their support of the plan. Among the signatories were two civilian groups that until recently supported Pinochet -- the rightist National Party and a conservative union movement.

Some analysts report indications that the document has also created a wait-and-see attitude within the ranks of the armed forces -- who are known to be nervously monitoring the human rights trials of former top military men in neighboring Argentina. The parties' accord calls for avoidance of retribution by either side in any future transition.

Fresno did not include the Communists in the negotiating sessions. Pinochet has repeatedly said he wants Marxism excluded from any future Chilean government.

The exclusion of the Communists was the biggest sticking point in the negotiations among the representatives of the other 11 parties, party leaders said.

In an interview, Molina said Communist Party participation in a civilian-run system was not "a priori" ruled out, but all parties would have to swear loyalty to democratic principles.

For the Communists, who adopted a strategy of "popular rebellion" in 1980, the accord may prove a formidable foil. Observers point out that the party, which traditionally was inclined to political alliances and fearful of isolation, is now relegated to the left margin of the political spectrum, along with the Revolutionary Leftist Movement guerrillas.

"The presence of the Communist Party could have disturbed others, and some of its declarations, inciting violence, were incompatible with the call for reconciliation," Molina said.

"The Communists say that in a democratic government they would act differently; we are saying that when we have power these will be the rules of the game." A few other Chilean parties proclaimed Marxism in the past, but they operated within the democratic system when it existed.

"The accord was a message to the military that the democratic opposition is also concerned about Communist activity, and that unlimited revenge will not be unleashed on the armed forces once the civilians take power," said a Western European diplomat.

The diplomat echoed a widely heard view following last week's violence that the outbreak did not overly strain Fresno's delicate efforts.

The observers said both the government and the opposition seem now to be trying to create dissent within the ranks of the other.

"The agreement isolates Pinochet, but it can be dangerous if he can get the accord's participants to fall into arguing among themselves, while at the same time the momentum gained by social mobilization through street protests is lost," said Jorge Schaulsohn, a lawyer and activist with the small, center-left Radical Party. "He did it in 1983."

Schaulsohn supports the accord, but said he worries that too much may be given away in order outflank the government on the right. Exclusion of the Communist Party signals the isolation of the sectors that have been most combative against the military, he added.