The Third Stage of Development of Buddhist Sangha,
The Transition of Power to Arrange the Affairs of
Buddhist Order Community Came to All Bhikkhus:

The small society of the Buddhist Sangha, with the passage of time, thus, became a big society. The functions of the Buddha and the Bhikkhus gradually increased. The method of work was changed along with the changing social situation. The method of admission to the Buddhist Order Community, supposed to be the main function of Bhikkhus, was changed. The function of giving the upasampadā Ordination was transferred to the Buddhist Community or Sangha.

This is the third transition of power: in the beginning the power was in the hands of the Buddha only, in the second stage this power was transferred to every senior and highly qualified Bhikkhu. Decision-making was an individual process. In the third stage this individual power was transferred to all Bhikkhus to function on behalf of the Sangha or Community.

Having considered this transition in decision-making power, we find three political systems, or governmental forms: the first may be likened to a monarchy, the power being vested in the hands of one person; the second is that the power of monarchy is transferred to the oligarchy or aristocracy, the power of decision-making then being vested in the hands of a few, the third is that the power of few is transferred to many – that is democracy.

The style of functioning of the Buddhist Sangha in the third stage is democratic, both in form and in spirit. This form can be said to have been designed by the Buddha. It will not be too fanciful to say that the Buddha was the first to have thought of and to have formed a democratic government. According to the Mahāvagga Vinayapitaka the Blessed One on this occasion, after having delivered a religious discourse, thus addressed the Bhikkhus:

I abolish, O Bhikkhus from this day the upasampadā ordination by threefold declaration of taking refuge, which I had prescribed. I prescribe O Bhikkhus, that you confer the upasampadā ordination by a formal act of the Order in which the announcement (Ñatti) is followed by three questions.  And you ought, O Bhikkhus, to confer the upasampadā ordination in this way:

Let a learned, competent Bhikkhu proclaim the following announcement (ñatti) before the Sangha:
Let the Sangha, reverend Sirs, hear me. This person N.N. desires to receive the upasampadā ordination from the venerable N.N. with the venerable N.N. as his Uppajjhāya. If the Sangha is ready, let the Sangha confer on N.N. as Uppajjhāya. This is the ñatti (announcement). Let the Sangha, reverend Sirs, hear me. This person N.N. desires to receive the Upasampadā ordination from the venerable N.N. The Sangha confers on N.N. the Upasampadā ordination with N.N. as Uppajjhāya. Let any one of the venerable brethren who is in favour of the Upasampadā ordination of N.N. with N.N. as Uppajjhāya be silent, and any one who is not in favour of it, speak. ‘And for the second time thus speak to you: Let the Sangha (& C., as before). And for the third time I thus speak to you. Let the Sangha,(& C., as before). ‘N.N.’ has received the Upasampadā ordination from the Sangha with N.N. as Uppajjhāya. The Sangha is in favour of it, therefore it is silent. Thus I

This affair of Sangha is finished by the consent of all Bhikkhus in the assembly. There was no question of anyone refusing that resolution. This power is vested in the assembly. It is not the majority accepting the affairs of the community, but unanimity is supposed to be the satisfaction of the assembly. The minority of the Sangha is also respected. All Bhikkhus in the assembly or in the monastery have equal right to do all Sangha affairs.

Development and evolution of the Sangha organization cannot be said to stop here but they were on-going. All Sangha affairs, such as distribution of social welfare within temple, were also vested in the assembly of the Sangha. The qualities of both the pupils and preceptors were being developed continuously on the basis of experience and social environment. The limitations, laws and orders were gradually increasing with changes of situation.

The development of Sangha organization was gradually improving both in respects to procedure and to the members of the community. A wrong deed or inappropriate action of the Bhikkhus was always submitted to be considered and corrected by the assembly of the Sangha. Such an action, after undergoing consideration, would form the basis of enacting new laws and orders for being the central principle of conduct of all Bhikkhus, both new and old, to follow. The Sangha society was not a fully ideal and static society but it was dynamic and changing. There was, therefore, need for continuous improvement. With the passage of time there were many Sangha affairs and so there were requirements, regulations, laws, and orders to run those affairs.

Dr.Phramahachanya Khongchinda

Full text here, page 188 for the Sangha discussion.