Scenes of murder, arson and mayhem in Port-au-Prince last Sunday should leave no doubt that Haiti's current military leadership is either totally ineffectual or fully implicated in the wanton slaughter of an unarmed citizenry desirous of political change through peaceful means.

But is the military really ineffectual? For months the ruling National Council of Government refused to provide the security needed to carry out the electoral process. In fact, the government looked the other way as democratic leaders were murdered in broad daylight.

Following indiscriminate killings of the lowly citizens during the month of July, the assassins became more selective. Witness the cases of Louis Euge`ne Athis and of Yves Volel. Athis, organizer of a democratic party with popular appeal, was hacked to death along with two associates by a peasant mob chanting anticommunist slogans and led by a rural constabulary attached to the Ministry of Internal Security and Defense. Athis was no communist.

As for Volel, a presidential candidate in the Western mold, he was shot in cold blood in front of police headquarters across from Gen. Henri Namphy's palace. A former classmate of Namphy at military school, Volel died clutching a copy of the constitution in one hand and his lawyer's robe draped over the other arm. He was protesting the fate of a prisoner detained illegally for more than one month.

Witness also the acts of sabotage carried out against the offices and homes of democratic political leaders and the offices of the Provisional Electoral Council, constitutionally empowered to oversee the electoral process. A pattern does emerge of an efficient band of murderers on the loose in Haiti.

These murderous incidents pale when compared with the latest actions witnessed by an international press corps and foreign observers who were at first elated by the prospect that Haiti was about to take a first step on the road to democracy. It is a cruel letdown for the humble citizens who longed so much to express themselves through the ballot box instead of with bullets.

I charge that the actions in Port-au-Prince must have been premeditated. The government had promised security for the elections when it moved swiftly last Thursday to wrest control of the streets from the self-defense groups, or vigilantes, that sprang up to provide protection to their neighborhoods.

Gen. William Regala, minister of internal security and defense and the No. 2 man in the three-member junta, had bristled at the "usurpation of power" by the neighborhood groups. And for the first time in weeks he showed his mettle. Army troops in battle dress began patrolling the streets. They even shot down some members of the defense groups, thereby proving their effectiveness. Peace was restored for two days, prompting election officials to be-come optimistic in the 11th hour that successful elections were still possible.

The same troops were patrolling Saturday night and Sunday when the machine-gun-toting thugs set fire to the radio stations, silencing Haiti's independent voices; when the goons ransacked the homes of some electoral council members, desecrated churches and slaughtered citizens lining up to vote.

Regala owes his nation -- and the world -- an explanation about his pledge of security for the election. Was he overruled, and by whom? What about Namphy, who, shedding crocodile tears, would have us believe that he will step down, as scheduled, on Feb. 7, 1988, and turn power over to a civilian president "duly elected"? Who would oversee this election, with the electoral council dismissed and most members in refuge in foreign embassies? Under what rules would it take place? Certainly, few citizens would dare participate in such a caricature of an election, reminiscent of similar exercises under the Duvaliers, father and son.

There can't be any democracy in Haiti as long as the current military, allied to the Duvalierist thugs, continues to have carte blanche to terrorize, kill and maim a defenseless citizenry that has clearly repudiated it.

The writer, a former Wall Street Journal reporter and an opponent of the Duvalier regime, is publisher of the Brooklyn-based weekly Haiti-Observateur.