They are pressing for a nonpartisan electoral commission, an end to military recruitment, and army and police forces free from Sandinista political control.
It recommends political concessions, but asserts that the army must remain under Sandinista control.
There are serious obstacles ahead, especially the question of separating the army from Sandinista political control.
All she did was name a commission with strictly limited powers to "assist" the police, still under Sandinista control.
Mr. Ortega also criticized plans to let municipal governments create new police forces outside of Sandinista control.
Among the changes offered were easing Sandinista control of the army and the police, and guaranteeing "free and honest elections."
They argue that the Sandinista control of the security forces means that business and landowners cannot be assured of police protection in case individuals or organizations try to take over their property.
Most Indian rebel factions have been pacified in one way or another, and Sandinista control of the area appears firm.
Their supporters say the Sandinistas are doing their best to comply with the Arias plan; critics say they are only playing for time, to weaken the contras before reasserting Sandinista control.
Diplomats say that a closer examination of the attack strongly suggests complicity at the highest levels of the country's army, which remain under Sandinista control although the Sandinistas lost the elections in 1990.