In my view it is impossible to separate any human action from politics. In The Human Condition, while commenting on Aristotle’s bios politikon, Hannah Arendt explains how, from all activities, there are only two that define the political condition of human communities, being action and speech. Whether present or not in the original intentionality of designers and architects, I believe design is a political statement and that it has the power of translating sociotechnical assemblages into action and speech. Perhaps the process of translation will not always be clear and transparent, but design can, simultaneously, speak for its “conceivers” and/or “users” and provoke actions of sociospatial transformation, as well as actions of usage of certain parts of space.
I think that processes of territorialisation, and therefore spatial control and management, explain how action and speech are rendered into spatial configurations by the hands and intentions of designers (and the social networks behind them). There are necessarily two moments for this translation to occur.
The first and most obvious is the one that precedes planning/building, dependent on the social, cultural, political and economic arrangements that make the design and its implementation possible. It is usually expressed in the intentions of the designer and the physical potential/limitations of an urban set.
The second moment relates to the possibilities of appropriation of that designed space by the people who will occupy/use it. This part of the translation does not necessarily depend on the design settings but can be influenced by it.
Thus, directly addressing the question, the limits of design to be political depend on the combination of these two moments. Based on this idea of a territorial translation that escapes the power of the designer, and despite the fact that it counts for half of the equation, I also dare to say that design is never enough. The power of the political voice of a design will always be dependent on the relationship with its occupants/users and the way a territory is constituted – and therefore the ways in which spaces and places are used by the public. Design and its sociotechnical constituents can, thus, limit or encourage forms of appropriation and, consequently, its own political voice.
For instance, the institutional and regulatory components of a design are important parts to be considered in the way a territory defines its boundaries and possibilities for use and appropriation. The current wave of privately-manned public spaces in cities like London (and Rio de Janeiro) serves as an example, when the possibilities of occupation and usage are not only defined by the physical constitution of places but also, and very strongly, by the practices and technologies that govern and regulate what kinds of behaviours are allowed and where. We must recognize and understand these processes, and think through ways of counteracting, with the help of design, this movement of weakened urban commons.
 Hannah Arendt, The Human Condition (University of Chicago Press, 1958)