In Perdido Street Station, a significant plot device is dedicated to the development of a crisis engine, something that would us to tap into crisis energy. Crisis energy is perpetual motion. Crisis energy takes the decisive moment that something changes, and uses that feed into more and more power for that change. Crisis energy is a part of being, by the very nature of being you are already in crisis, just waiting to tap into it to do anything. This seems close to the understanding of potentia by Negri. Power that comes from living being that allows one to constantly change, morph, become something else entirely. We don't know what crisis can do.
In The Scar, a different type of power is sought after, the power of the possible. The power of the possible sword, or the possible letter. The explaination of the possible is given with the possible sword. Uther Doul carries with him a strang piece of technology, called a possible sword. When turned on, it doesn't just hit the target he actually hits, it hits all possible targets to a certain degree. The more possible, the more they are hit. The power of the sword isn't to become something else (a la crises) but to be or not to be whatever it possibly could be.
Now, maybe crisis energy and the possible sword are bad examples. However, the way Mieville describes the tension between the two is a great description of the tension between the two politics of Negri and Agamben.
From The Scar:
[H]is conviction that underlying the facticity of the world, in all its seeming fastnass, was an instability, a crisis pushing things to change from the tensions within them.
In the possibility mining that Uther Doul had just described Bellis saw a radical undermining of crisis theory. Crisis, Issac had once told her, was manifest in the tendency of the real to become what it was not. If what was and what was not were allowed to coexist, the very tension -- the crisis at the center of existence -- must dissipate. Where was that crisis energy in the real becoming what it was not, if what it was not was right there alongside what it was? (p. 396).