Participatory budgeting, by which in New York City open public assemblies, in the district of each city councilperson choosing to participate meet and hear and debate proposals for the use of those limited capital funds allocated at the discretion of the council person. Their recommendations to him or her are in practice largely effective. It is a major approach to the difficult question of how to make governmental decisions both reasonably efficient and well structured, and at the same time really democratic, participatory, and transparent, all at the fundamental grass-roots level. 
The approach underling participatory budgeting can have, if fully pursued by a comprehensive Participatory budgeting system, a fundamental and quite radical impact on the nature of local government. In two distinct ways: democratic participation, and democratic decision-making. As to participation it is a method of permitting input from citizens in a detailed, concrete, transparent fashion, open not only to essentially reactive public reactions to governmental proposals, but also permitting the injection of citizens own ideas and proposals into the political process. As to decision-making, it represents a degree of decentralization from the larger city-wide urban level to the districts of the 51 council members (the discussion here focuses on the program in New York City, now , thus approaching its third year of use), a degree of decentralization approaching the old town meeting forms of direct democracy widely used at that much smaller scale in the early days of the United States in a largely rural society..
Participation could thus be much broader, more direct, and democratic. And decision-making could be much more directly open, grass-roots, and transparent.
In practice, the implementation of such a fully pursued comprehensive approach in New York City is very much more constrained and piece meal, very limited as to the subjects of participation and not pursued very far in the in decision-making process. . The scope of participation limited to the amounts in any council persons’ discretionary budget, typically around $1,000,000 out of a total city budget of $100,000,000,000, including capital expenditures, typically about $20,000,000,000. The council persons’ discretionary budgets are today limited to capital expenditures; operating costs of programs whether for job creation, job training, early childhood education, planning of transportation routes, zone changes, land use planning senior programs, etc., etc. are not included. Typically, city agency capital budgets are not reviewed, although they vastly exceed council discretionary budgets. The results of the neighborhood assemblies are not binding on council persons, and indeed open to being manipulated by them with an eye to solidifying a political base of support in the district.
The issues involved in the expansion of participatory budgeting as it now exists in New York City, to what a full-fledged comprehensive approach might be, are substantial, both politically and conceptually. Politically, the simple fact that only 9 of 51 council persons have agreed to participate, despite a multi-year effort, speaks volumes: active “outside” participation is seen as an infringement on their discretion even as to the expenditure of their limited discretionary funds; the concept of expansion to other budgetary decisions, and even policy decisions, may well not be greeted enthusiastically by most elected officials. A mayor’s position may be more open. Wider participation may be seen as a limitation on his discretion also, presenting new political problems. It may also be seen as a substantive shift of power towards the mayor, as the original establishment of the 59 community boards in New York City was seen by then Mayor Wagner.
But to the conceptual problems. Simply to list them:
How should the scope of assembly-type participation be defined? All capital expenditures taking place in or affecting a district? The district operating budgets of all city agencies operating in the district? Some set proportion?
How can city-wide, as well as district-level, interests be taken into account? In the early models of participatory budgeting, e.g. Porto Alegre, sectoral assemblies were established, which included representatives of every district but examined the distribution of expenditures among districts to insurance equity.
How should districts be defined for purposes of participation? As it is, they are city council electoral districts. But electoral districts are notoriously defined by political result. Community district lines, postal Zip codes, school and operating agencies boundaries (already subject to a mandate for limited congruity). The process of defining electoral boundaries has resulted in massive data that could result in new district definitions. How should the problem be handled?
There is a history of expanding democratic participation in the City which needs to full reviewed. Perhaps most critically is the nature and role of Community Boards. They are an explicit move in the direction of decentralization of decision-making power and participation in public deliberations, including already a specific if limited role in budgeting. The present arrangement in effect creates a competing line of organization of local participation. Can the two be merged? Could they be integrated, by mutual consent, in deliberations? Should there be an effort to make the logical but even bigger move, to merge the boundaries for council districts and community boards, a logical but potentially treacherous political goal?
Can the innovative procedures for democratic participation pioneered by participatory budgeting movement be expanded to affect the city as a whole? Could the grass-roots strength of the existing assemblies be marshaled in a joint form, perhaps borough-wide (as community boars now are) or an assembly of assemblies, in any event ins such fashion that support for the process can be politically marshaled?
What should the city government’s role in the process be? Clearly, independence is sine qua non. But wouldn’t funding without control except for graft be a major support for the process? How far can volunteer and foundation-funded staffing go, what role should city agency employees be asked to play or be limited to playing?
How should participation in expenditure decisions be related to revenues derived from decisions as to taxation and handling of city economic development policies? Should not, for instance, the sale of city-owned property, or the privatization of service it is the city’s responsibility to deliver, e.g. garbage collection, security, building code inspection, park maintenance, be subject to participation?
Are there any structural changes in the organization of city government that might enhance the participatory budgeting process? For example, history the City Planning commission had the responsibility to review and act on the city’s capital budget before it went to the City Council. Might restoring its role provide a non-partisan and expert overview of local decisions that would be of benefit to all concerned? It might not be greeted enthusiastically by a mayor fearing diminution of his (or her?) own power—unless, that is, it is in fact seen as a move towards further modernization and efficiency, as well as a democratically related improvement in a difficult and complex process?
Participatory Budgeting is grounded in the desire to expand the scope of democracy in local government. That demand is sometimes in tension with the demand for social justice; often the two are seen as parallel but separate demands aiming at the creation of the Just City. But sometimes it is frankly generally recognized that the two can be in tension with each other, and one can be pursued without necessarily a commitment to the other. Where does the participatory budgeting process in New York stand on the issue? Is social justice a major element in its philosophy and practice? Can there be general guidelines for the objectives a proposal considered in the participatory budgeting process should follow (see 10. below?)
Should there be a set of principles expected to be followed by all decisions made through the process, e.g. non-discrimination, affirmative action, weighing of environmental consequences, social impact statements, inequality reduction?
How politically controversial should advocates for the participatory budgeting process get? Should they only promote the policy where those in power are friendly to it, or should they see it also as a part of an effort to further democracy where those in power are reluctant to potentially weaken their power by its introduction? Should proponents of the process be willing to be critical of the opposition to it, take on their arguments against it directly at their home base as well as commenting on it internally? Should they advocate for the City Council to adopt policies encouraging participatory budgeting in all districts, regardless of individual council members desire? Or format formal procedures for participatory budgeting that could be adopted by any council member at his or her option – perhaps creating controversy in some non-adopting districts? Or should they shrink back even from that?
Participatory budgeting can be a significant step forward in the exploration of ways of achieving real democracy at the grass-roots level, immediately in capital budget planning (by itself a key element in the shaping of the built environment and social structure of cities), but also more generally in the search for the mechanisms by which truly democratic planning and decision-making might be accomplished, keeping in mind the legitimate needs for efficiency and the practical needs for political realism.
But participatory budgeting can also be a will-o-the-wisp, or worse. It can be used simply as a sophisticated way for those already in position of political power and influence to get information about what some active among their constituency think and want, akin to polling, but with the added advantage of giving the respondents the feeling they are participating in decision-making, While in fact their participation if at a minimal level of power over a minimal range of decisions. Thus it can be a co-optive mechanism using sophisticated technical forms to reinforce existing patterns of conduct by those in power. The devil is both in the details and, perhaps even more, in the broader perspective in which it viewed.
 The process, and a quite general statement of its goals, are at: http://www.participatorybudgeting.org/wp-content/uploads/2012/07/Rulebook.pdf. What follows may be seen as a commentary addressed to those goals and the strategic issues involved in their possible implementation.
 A minimum. See http://council.nyc.gov/downloads/pdf/budget/2014/14budget.pdf for a simplified presentation. Some of the funds further have specific restrictions, e.g. for non-profit social service agencies, senior services, youth programs, etc.