It was a meeting of the men known as the "Three A's" of Nicaragua's counterrevolutionaries -- leaders Adolfo Calero, Arturo Cruz and Alfonso Robelo -- plus one more "A" -- Assistant Secretary of State Elliott Abrams.

In a showdown April 15 culminating nine months of dissension among the three contras, as the rebels are called, Abrams laid down the law. He said they would have to cooperate with each other and present a more attractive image to the world or they weren't going to get the $100 million in aid being hotly debated in Congress, participants said.

"A boil that was building has been lanced," an administration official said afterward. The rebel leaders went away relieved that they had made a breakthrough toward what Cruz called "a complete settlement."

It was another peculiar incident in the career of the contras, an armed force of at least 10,000 gritty peasant partisans led by gray-suited executives who insist they are nationalists but often end up waging their battles with equal zeal in the mountains of Nicaragua and on Capitol Hill.

Abrams' meeting was the turning point, administration officials said, in a campaign by an unlikely coalition of Nicaraguans and Washington personalities, including Sen. Nancy Kassebaum (R-Kan.) and Robert Leiken of the Carnegie Endowment for International Peace, to restyle the anti-Sandinista movement to broaden its base of support.

As a result, an eight-man commission of the United Nicaraguan Opposition, the main contra alliance which Calero, Cruz and Robelo head, spent all week in meetings in Miami to hammer out changes to end the internal tug-of-war. The three contra leaders are expected to meet Monday in Miami to give final approval to the organizational changes.

Officials said Abrams successfully rode the contra reform issue to become the key player in a Central America policy that has bounced between administration offices for the past year. Abrams, officials said, concluded in past months that the contras were stalled politically in Nicaragua and needed a more convincing civilian leadership to ward off charges of criminal activities by contra guerrillas and to come up with a compelling political program.

The State Department has thrown some of its weight behind Cruz and Robelo, who are demanding changes the two leaders said will tip the balance of power inside the alliance to make it more democratic. Up to now Calero has enjoyed dominance as the head of the Nicaraguan Democratic Force (known by its Spanish initials as the FDN), which claims more than 14,000 armed guerrillas, a disputed figure. Robelo leads a badly battered force of no more than 500 fighters in southern Nicaragua, while Cruz commands nothing more than his own reputation as an honest man.

But administration officials and reformers have also made it clear there will be no move at this time to change any personalities in the contra leadership. During this year's congressional debate allegations swirled around Calero as the top civilian chief, as the contras were accused of dealing cocaine, smuggling arms and pilfering donations. No criminal activities have been proved against anyone in the FDN, although Sen. John Kerry (D-Mass.) is leading an effort to open a congressional inquiry.

Administration officials reaffirmed in recent interviews that Calero remains indispensable because he is an effective interlocutor with U.S. conservatives and also commands the allegiance of his controversial top military chiefs, principally Enrique Bermudez, a colonel in the former Nicaraguan National Guard. Bermudez, who is mistrusted by some anti-Sandinistas because of his ties to the Somoza-era guard, was described recently by a senior administration official as "a good organizer and manager type who is not replaceable at this time."

Last August, only two months after the United Nicaraguan Opposition was formed, Cruz and Robelo signed an agreement with Calero in Honduras in which the FDN agreed to use the coalition's insignia on their uniforms and in their camps. But when Cruz and Robelo visited an FDN camp in Honduras in March, "they could have been from the Miami Chamber of Commerce," said one Nicaraguan who was there. They noted "a complete and calculated lack of interest" in the alliance among FDN troops and leaders.

Minutes of the 13 United Nicaraguan Opposition meetings between July and February, obtained by The Washington Post, show there was no detailed discussion of military matters. When ranking alliance members asked Calero for a briefing at a Miami meeting in February they got "cocktail party anecdotes," one disgruntled participant said.

It took Cruz seven months of pushing to set up a human rights commission, the alliance's only significant measure.

"You have an FDN clique that just doesn't want to let go of their toy," said one alliance member.

Now Cruz is proposing to set up new "secretariats" inside the United Nicaraguan Opposition to institutionalize control over some military and money matters and to give decision-making power to contras inside and outside the FDN.

But many contras and some administration officials said it remains unclear if or how these changes would have any effect on the guerrillas fighting inside Nicaragua.

"Their basic allegiance is not to the FDN or Cruz," said one official. "It's to the guy who leads 15 of them into the mountains to fight."

Another unknown about reform is Cruz's staying power, U.S. officials and even his close colleagues said. The avuncular and professorial Cruz, 62, served as a member of an early Sandinista junta in 1980 and as Nicaragua's ambassador in Washington until he resigned in protest in late 1981. He returned to Nicaragua briefly to run for president in November 1984 elections, but yielded to conservatives in his coalition who insisted that he pull out of the race.

From the day he joined in founding the United Nicaraguan Opposition in June 1985, Cruz warned that he might not last long.

"He's a thinking man's public servant, not a politician," said one conservative Nicaraguan who has known Cruz for years.

"We don't really know if he's got the fire in his belly," worried a Nicaraguan exile friend.

Calero, 55, a Notre Dame graduate, was head of a Coca-Cola franchise in Nicaragua, and was jailed in 1978 for organizing a businessmen's strike against former ruler Anastasio Somoza. He joined the FDN leadership in 1983 in an image clean-up sponsored by the CIA.

Calero said he is proud to have mastered a shadowy international arms market to purchase weapons from Poland, Czechoslovakia, and even China.

Robelo, a millionaire chemical engineer and cotton farmer, is regarded with suspicion by many anti-Sandinista Nicaraguans because he served as a member of the Sandinistas' first junta in 1979. He was civilian manager for the mercurial comandante Eden Pastora until they feuded in 1984.